Adding Cypress framework

Fixes #513

Cypress Version: 9.5.3

Commands

The app needs to be running in the background. Run npm run start and then the following commands.

Opens the Cypress GUI, we can run the integration tests by clicking on the test files.

Will run the tests on the command line (headlessly).

[x] type in some html, hit save. there should be something in the localstorage with "untitled.." in name
[x] change the creation title, it should auto save in localstorage. Also a toast should show up saying it was saved.
[x] Clicking "OPEN" should open the saved items pane.
[x] Saved items should show up in the saved items pane
[x] "Add Library" should open the add library modal. Selecting any library from dropdown should change the URL in the textarea fields. Selecting another library should add the URL in a newline in the textarea fields.
[x] Clicking on the header buttons should pop up the modal.
[x] Clicking on the layouts should accordingly change the layout.
[x] Perform basic JS operations in the console.