[Task](ui): Change imports from deprecated Javascript components to Typescript (incl. Portal) and tidy up

[guoda-puidokaite]

Task Description

When all components in @cloudoperators/juno-ui-components have been migrated to Typescript, we should swap over any remaining deprecated imports to the new migrated ones. After all, delete all migrated Javascript components from deprecated_js.

List of potential dependencies

• All components depending on Portal should be migrated before making the change. Last component to be merged is DateTimePicker [TASK](ui): Migrate DateTimePicker component to TypeScript  #227.

Sub-tasks

• Make sure that all migrated components import Typescript components instead of deprecated Javascript ones (especially Portal and AppShellProvider).
• Change index.js in AppShellProvider to index.ts.
• Delete all migrated components from deprecated_js.
• Check Storybook
• Test Supernova, Elektra
• Fix all errors related to npm run typecheck
• Check if npm run build is working (note: errors already existed before, need to fix in another ticket)
• Check that npm run lint is working correctly and fix all tslint errors

Related Issues

• [EPIC]: @cloudoperators/juno-ui-components migrate UI Components to TypeScript #168

[guoda-puidokaite]

Tested Supernova and Elektra Key Manager with @ArtieReus, focusing on Portal-related functionality

Supernova ✅

• Clicked on the "Silence" button from the alerts list and from the alert details view
  • then clicked on the silence duration dropdown to verify that everything is visible and stacked properly on top of each other
• Checked that the Panel header is visible and doesn't disappear underneath the PageHeader
• Scrolled down to make the content disappear underneath the PageHeader

Elektra Key Manager ✅

• Opened a Panel to see that it opens correctly above the Elektra PageHeader
• Tested the DateTimePicker
• Tested Select

CC: @edda @barsukov @andypf