feat:rich textbox type form element implementation

[harshilshah99]

This pull request makes the following changes

• Fixes Issue 13: Implementation of Rich text box type form element #16

Goals

• Create an interface for the base form object.
• Install Angular Material as the dependency for the library.
• As per the reference implementation, convert the code to handle the angular material input component.
• Implement test cases for the component.
• Prepare proper documentation for the implementation.

Implementation

Used a npm library @kolkov/angular-editor for rich text box type form

npm i @kolkov/angular-editor

npm i angular-font-awesome

Setting up config for the editor in the app.conmponent.spec.data.ts

config: {
        editable: true,
        spellcheck: true,
        height: '15rem',
        minHeight: '5rem',
        placeholder: 'Enter text...',
        translate: 'no',
        defaultParagraphSeparator: 'p',
        defaultFontName: 'Arial',
        toolbarHiddenButtons: [
          [
            'justifyLeft', 'justifyCenter', 'justifyRight', 'justifyFull', 'strikeThrough', 'subscript', 'superscript', 'indent', 'outdent', 'undo', 'redo',
          ],
          [
            'fontSize', 'textColor', 'backgroundColor', 'customClasses', 'link', 'unlink', 'insertVideo', 'insertHorizontalRule', 'removeFormat', 'toggleEditorMode',
          ],
        ]
      },