fix: use quarkus compatible classloader

[caalador]

Use a classLoader that is
compatible with quarkus for
default i18N translation.

part of vaadin/flow#18977

[caalador]

Depends on vaadin/flow#19136
Also proposes update add-on from 2.0 to 2.1 meaning that 2.0 should be branched out from main branch.

[mcollovati]

Also proposes update add-on from 2.0 to 2.1 meaning that 2.0 should be branched out from main branch.

Is it reasonable to have two separated commits for version bump and the instantiator change and then do a rebase and merge instead of squash?

[mcollovati]

A minor nit: swapping the order of the commits would make both of them compilable once we have the new Flow snapshot. With the current order (first code changes than Flow bump) the first commit will be broken.

[mcollovati]

It would be nice to add I18n test (normal usage + background thread), but we can do it in another PR.
Probably there are also other features missing some test

[caalador]

Now the test is there and the assertions should be build in the correct order.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[vaadin-bot]

Hi @caalador and @caalador, when i performed cherry-pick to this commit to 2.0, i have encountered the following issue. Can you take a look and pick it manually?
Error Message:
Error: Command failed: git cherry-pick d7ac1aa
error: could not apply d7ac1aa... fix: use quarkus compatible classloader
hint: After resolving the conflicts, mark them with
hint: "git add/rm ", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".

[mcollovati]

Was already picked manually