Translate Theia using language packs

[msujew]

What it does

Addresses another open issue from #9538: Localization of Theia using (mostly) vscode language packs.

Let me know if you find any strings that are user facing and not translatable yet.

Be aware that not everything is translated in here, see #10188.

How to test

1. Download and install a vscode language pack of your choice.
2. Run the application and look out for missing/erroneous translations.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[jbicker]

Theia is successfully translated. Thanks!

[vince-fugnitto]

Given the impact of these changes, we might have wanted to have additional reviewers from various companies to offer input (no request for reviewers as is). I don't believe the pull-request description (or commit) documents and clarifies enough the impacts, and design.

See discussions:

• menu: update go main-menu #10299 (comment)
• menu: update go main-menu #10299 (comment)

[msujew]

@vince-fugnitto While it's true, that I requested no reviews from anyone via GitHub (mea culpa), I asked for reviews multiple times during the weekly dev-meetings, even confirming with @marcdumais that everything should be merged before the end of this week.

On another note, the actual design was documented in #9538 (and a bit in #9708). I.e. translating Theia using language packs where possible, which leads to the coupling of Theia and IDs used in the vscode language packs. Trying to minimize the effort of translating Theia by using the already translated vscode language packs was part of the design. This PR just addresses the open issue from #9538 that Theia wasn't actually translated using the design proposed in there.

[vince-fugnitto]

@vince-fugnitto While it's true, that I requested no reviews from anyone via GitHub (mea culpa), I asked for reviews multiple times during the weekly dev-meetings, even confirming with @marcdumais that everything should be merged before the end of this week.

The problem was that I feel this should have probably been documented better in the pull-request description, commit message and in some guideline, and for the most part fell under the radar as there were many localization pull-requests opened simultaneously. I would have wanted more feedback from the community about this one (especially since we are now so tightly coupled with vscode and leak plugin information across the framework (something usually reserved for the plugin system itself).

On another note, the actual design was documented in #9538 (and a bit in #9708). I.e. translating Theia using language packs where possible, which leads to the coupling of Theia and IDs used in the vscode language packs. Trying to minimize the effort of translating Theia by using the already translated vscode language packs was part of the design. This PR just addresses the open issue from #9538 that Theia wasn't actually translated using the design proposed in there.

Unfortunately I'm not sure everyone was aware of that coupling. Given they are plugins I expected it to be isolated to the plugin-system itself and not leaked across the framework. I did not expect references to vscode keys everywhere in the codebase. That's of course my own opinion.