fix broken URLs and automate broken URL checks #70

This commit:
- Fixes broken URLs using archive.org or other references.
- Replaces tenforums.com URLs with better documentation as they tend to return HTTP status code 403 to tests and also are low quality source.
- Changes all insecure http sources to https alternatives
- Adds integration tests to check for broken URLs
  - There's logic implemented for having a delay inbetween when sending requests to same domains, however it's not used as the sources can respond to totally parallelized requests.
- Run test pipeline weekly to get notified about broken URls without commits

package-lock.json

@@ -16,6 +16,7 @@
         "@juggle/resize-observer": "^3.3.0",
         "ace-builds": "^1.4.12",
         "core-js": "^3.9.1",
+        "cross-fetch": "^3.1.4",
         "file-saver": "^2.0.5",
         "inversify": "^5.0.5",
         "liquor-tree": "^0.2.70",
@@ -5772,6 +5773,14 @@
         "sha.js": "^2.4.8"
       }
     },
+    "node_modules/cross-fetch": {
+      "version": "3.1.4",
+      "resolved": "https://registry.npmjs.org/cross-fetch/-/cross-fetch-3.1.4.tgz",
+      "integrity": "sha512-1eAtFWdIubi6T4XPy6ei9iUFoKpUkIF971QLN8lIvvvwueI65+Nw5haMNKUwfJxabqlIIDODJKGrQ66gxC0PbQ==",
+      "dependencies": {
+        "node-fetch": "2.6.1"
+      }
+    },
     "node_modules/cross-spawn": {
       "version": "6.0.5",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-6.0.5.tgz",
@@ -12658,6 +12667,14 @@
         "semver": "bin/semver"
       }
     },
+    "node_modules/node-fetch": {
+      "version": "2.6.1",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.1.tgz",
+      "integrity": "sha512-V4aYg89jEoVRxRb2fJdAg8FHvI7cEyYdVAh94HH0UIK8oJxUfkjlDQN9RbMx+bEjP7+ggMiFRprSti032Oipxw==",
+      "engines": {
+        "node": "4.x || >=6.0.0"
+      }
+    },
     "node_modules/node-forge": {
       "version": "0.10.0",
       "resolved": "https://registry.npmjs.org/node-forge/-/node-forge-0.10.0.tgz",
@@ -25705,6 +25722,14 @@
         "sha.js": "^2.4.8"
       }
     },
+    "cross-fetch": {
+      "version": "3.1.4",
+      "resolved": "https://registry.npmjs.org/cross-fetch/-/cross-fetch-3.1.4.tgz",
+      "integrity": "sha512-1eAtFWdIubi6T4XPy6ei9iUFoKpUkIF971QLN8lIvvvwueI65+Nw5haMNKUwfJxabqlIIDODJKGrQ66gxC0PbQ==",
+      "requires": {
+        "node-fetch": "2.6.1"
+      }
+    },
     "cross-spawn": {
       "version": "6.0.5",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-6.0.5.tgz",
@@ -31409,6 +31434,11 @@
         }
       }
     },
+    "node-fetch": {
+      "version": "2.6.1",
+      "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-2.6.1.tgz",
+      "integrity": "sha512-V4aYg89jEoVRxRb2fJdAg8FHvI7cEyYdVAh94HH0UIK8oJxUfkjlDQN9RbMx+bEjP7+ggMiFRprSti032Oipxw=="
+    },
     "node-forge": {
       "version": "0.10.0",
       "resolved": "https://registry.npmjs.org/node-forge/-/node-forge-0.10.0.tgz",