Apply global styles for visual consistency

This commit centralizes the styling of key UI elements across the
project to ensure:

- Consistent look and feel.
- Enhanced code reusability.
- Simpified maintenance, improving development speed.

It establishes a uniform foundation that can be leveraged across
different parts of the project, even enabling the styling to be shared
across different websites (supporting issue #49).

Key changes:

- Apply the following shared styles globally:
  * Styling of code, blockquotes, superscripts, horizontal rules and
    anchors.
  * Vertical and horizontal spacing.
- Segregate base styling into dedicated SCSS files for clearer structure
  and increased maintainability.
- Remove custom styling from affected components, enabling global style
  reuse for visual uniformity, reduced redundancy, and enhanced
  semantics.

Other supporting changes:

- Rename `globals.scss` to `base.scss` for better clarity.
- Add `.editorconfig` for `.scss` files to ensure consistent whitespace
  usage.
- Remove `2` file from the project root, that was included in the source
  code by mistake.
- Remove unused font-face imports

src/presentation/assets/styles/_mixins.scss

@@ -118,3 +118,13 @@
     }
   }
 }
+
+@mixin set-property-ch-value-with-fallback($property, $value-in-ch) {
+  @supports (width: 1ch) {
+    #{$property}: #{$value-in-ch}ch;
+  }
+  // For browsers that does not support `ch` unit (e.g., Opera Mini):
+  $estimated-width-per-character-in-em: calc(1em / 2); // 1 character is approximately half the font size
+  $calculated-width-in-em: calc(#{$estimated-width-per-character-in-em} * #{$value-in-ch});
+  #{$property}: $calculated-width-in-em;
+}