Update to Angular 15

The move to Angular 15 was done by following the angular official documentation

The update introduced some major and minor changes.

Major changes :

• The UI has been reworked. The move to angular 15 introduced a move to CDK components, which meant breaking changes in the way some components were shown
  • Comparison between new UI (Left) and old UI (Right)
    • Main page - Local storage (without documents)
    • Main page - Local storage (with documents)
    • Main page - Local storage (closed nav, with documents)
    • Main page - Trash (without documents)
    • Main page - Trash (with documents)
    • Main page - Trash (closed nav, with documents)
    • Main page - Document options
    • Main page - Document infos
    • Main page - Themes
    • Document edition - Full page
    • Document edition - Full page with modifications
    • Document edition - Full page with modifications preview
    • Document edition - navbar syntax
    • Document edition - Themes
    • User settings
    • User profile
    • Restore a document from trash
    • History (functionality not currently working)
  • @angular/flex-layout has been completely removed. The solution to this deletion was the introduction of Tailwind as a sort of replacement.

Minor changes :

• Some angular dependency were manually updated :

    - @angular-devkit/build-angular": "^15.2.10"
  
    - "@angular-eslint/builder": "^15.2.1"
  
    - "@angular-eslint/eslint-plugin": "^15.2.1"
  
    - "@angular-eslint/eslint-plugin-template": "^15.2.1"
  
    - "@angular-eslint/schematics": "^15.2.1"
  
    - "@angular-eslint/template-parser: "^15.2.1"

• The src/test.ts file has been removed as it is no longer useful for karma execution. src/tsconfig.spec.json and angular.json were modified to account for this removal.

• Some adjustements were made to the UI were made to make MUTE easier to use on a smartphone/tablet

• Some changes were automatically generated by prettier