docs(v6): Update v6 StackBlitz set up and examples for JavaScript and Angular

[soundproofboot]

resolves #4199

Changes

• Update contents of static/code/stackblitz/v6/html to allow JavaScript examples to load correctly in StackBlitz.
• Update contents of static/code/stackblitz/v6/angular to allow Angular examples to load correctly in StackBlitz.
• Add IonicModule and standalone: true to all Angular examples that need an example.component.ts file.
• Update all Angular examples that use Ionicons to use addIcons method in component constructor, creating the component files if they did not exist.
• Update several other examples on case by case basis to include additional imports like CommonModule, FormsModule, or RoutingModule, etc as needed.
• Change type of version to string in global/Playground files to match how version is passed in Playgrounds component. I believe it was incorrectly typed but not used in a way that would throw an error. This was necessary to allow a branch for v6 only in loadSourceFiles where the mode is inserted in main.ts.

Additional Information

• To build v6 docs, add "v6" to versions.json and remove the "v6" entry in versionsArchived.json. This is not in the PR because v6 should not be in the build but will need to be rebuilt and redeployed to Vercel, and the link to the new build updated in versionsArchived.json.
• I also found I needed to fix a typo in version-v5 and version-v6/developer-resources/books.md to allow the build. (The link to https://developer.school has two colons but also seems to no longer exist).
• This PR does not yet include updates to any JavaScript examples. Any that use Ionicons need to be updated and the rest should be checked for any other issues.

[vercel]

@soundproofboot is attempting to deploy a commit to the Ionic Team on Vercel.

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