[TASK] EXT:install: Migrate `InfoBox` and `FlashMessage` to Lit

In the effort of removing jQuery from the Install Tool, this patch
migrates the `InfoBox` and `FlashMessage` components to custom Lit
elements.

Resolves: #101588
Releases: main
Change-Id: I755d88eafddb8ca57a0aef0345c1c6d282ee4b7e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80403


Reviewed-by: Andreas Nedbal <andy@pixelde.su>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Nedbal <andy@pixelde.su>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>