Fix unresponsive copy button on instructions modal

This commit fixes the bug where the "Copy" button does not copy when
clicked on download instructions modal (on Linux and macOS).

This commit also introduces several improvements to the UI components
related to copy action and their interaction with the clipboard feature.

It adds more tests to avoid regression of the bugs and improves
maintainability, testability and adherence to Vue's reactive principles.

Changes include:

- Fix non-responsive copy button in the download instructions modal by
  triggering a `click` event in `AppIcon.vue`.
- Improve `TheCodeButtons.vue`:
  - Remove redundant `getCurrentCode` function.
  - Separate components for each button for better separation of
    concerns and higher testability.
  - Use the `gap` property in the flexbox layout, replacing the less
    explicit sibling combinator approach.
- Add `useClipboard` compositional hook for more idiomatic Vue approach
  to interacting with the clipboard.
- Add `useCurrentCode` compositional hook to handle current code state
  more effectively with unified logic.
- Abstract clipboard operations to an interface to isolate
  responsibilities.
- Switch clipboard implementation to the `navigator.clipboard` API,
  moving away from the deprecated `document.execCommand`.
- Move clipboard logic to the presentation layer to conform to
  separation of concerns and domain-driven design principles.
- Improve `IconButton.vue` component to increase reusability with
  consistent sizing.

src/presentation/components/Code/CodeButtons/Save/Instructions/Data/LinuxInstructionsBuilder.ts

@@ -0,0 +1,93 @@
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { InstructionsBuilder } from './InstructionsBuilder';
+
+export class LinuxInstructionsBuilder extends InstructionsBuilder {
+  constructor() {
+    super(OperatingSystem.Linux);
+    super
+      .withStep(() => ({
+        action: {
+          instruction: 'Download the file.',
+          details: 'You should have already been prompted to save the script file.'
+            + '<br/>If this was not the case or you did not save the script when prompted,'
+            + '<br/>please try to download your script file again.',
+        },
+      }))
+      .withStep(() => ({
+        action: {
+          instruction: 'Open terminal.',
+          details:
+            'Opening terminal changes based on the distro you run.'
+            + '<br/>You may search for "Terminal" in your application launcher to find it.'
+            + '<br/>'
+            + '<br/>Alternatively use terminal shortcut for your distro if it has one by default:'
+            + '<ul>'
+            + '<li><code>Ctrl-Alt-T</code>: Ubuntu, CentOS, Linux Mint, Elementary OS, ubermix, Kali…</li>'
+            + '<li><code>Super-T</code>: Pop!_OS…</li>'
+            + '<li><code>Alt-T</code>: Parrot OS…</li>'
+            + '<li><code>Ctrl-Alt-Insert</code>: Bodhi Linux…</li>'
+            + '</ul>'
+            + '<br/>'
+          ,
+        },
+      }))
+      .withStep(() => ({
+        action: {
+          instruction: 'Navigate to the folder where you downloaded the file e.g.:',
+        },
+        code: {
+          instruction: 'cd ~/Downloads',
+          details: 'Press on <code>enter/return</code> key after running the command.'
+            + '<br/>If the file is not downloaded on Downloads folder,'
+            + '<br/>change <code>Downloads</code> to path where the file is downloaded.'
+            + '<br/>'
+            + '<br/>This command means:'
+            + '<ul>'
+            + '<li><code>cd</code> will change the current folder.</li>'
+            + '<li><code>~</code> is the user home directory.</li>'
+            + '</ul>',
+        },
+      }))
+      .withStep((data) => ({
+        action: {
+          instruction: 'Give the file execute permissions:',
+        },
+        code: {
+          instruction: `chmod +x ${data.fileName}`,
+          details: 'Press on <code>enter/return</code> key after running the command.<br/>'
+            + 'It will make the file executable. <br/>'
+            + 'If you use desktop environment you can alternatively (instead of running the command):'
+            + '<ol>'
+            + '<li>Locate the file using your file manager.</li>'
+            + '<li>Right click on the file, select "Properties".</li>'
+            + '<li>Go to "Permissions" and check "Allow executing file as program".</li>'
+            + '</ol>'
+            + '<br/>These GUI steps and name of options may change depending on your file manager.'
+          ,
+        },
+      }))
+      .withStep((data) => ({
+        action: {
+          instruction: 'Execute the file:',
+        },
+        code: {
+          instruction: `./${data.fileName}`,
+          details:
+            'If you have desktop environment, instead of running this command you can alternatively:'
+            + '<ol>'
+            + '<li>Locate the file using your file manager.</li>'
+            + '<li>Right click on the file, select "Run as program".</li>'
+            + '</ol>'
+          ,
+        },
+      }))
+      .withStep(() => ({
+        action: {
+          instruction: 'If asked, enter your administrator password.',
+          details: 'As you type, your password will be hidden but the keys are still registered, so keep typing.'
+            + '<br/>Press on <code>enter/return</code> key after typing your password.'
+            + '<br/>Administrator privileges are required to configure OS.',
+        },
+      }));
+  }
+}