Support per-layout translations entries

[romanz]

Following #4489.

Also, use layout names for translation font keys.

[github-actions]

core UI changes	device test	click test	persistence test
T2T1 Model T	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3B1 Safe 3	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3T1 Safe 5	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
All	main(screens)

[romanz]

I will reorganize the commits above, in order to separate the text-modifying edits into a separate commit (which can be dropped - to avoid UI changes).

[romanz]

i.e., there is no diff between 8952a98 and 4148e87, just reorged the commits' content by the above force-push.

[obrusvit]

Thank you. It works as expected, we can now specify different strings per layout and per language. There's one caveat though:

• if we misspell a layout name in en.json, then everything is OK because the mistake is caught in compile time 👍
• if we misspell a layout name in other lang, e.g. cs.json then it fallbacks to english version 🤔 I wonder if we can do something about it now.

Note that this problem is not new because if we miss the whole string in cs.json then we also get fallback to english version without any warning. I'd probably fix this issue separatedly.

[romanz]

• if we misspell a layout name in other lang, e.g. cs.json then it fallbacks to english version 🤔 I wonder if we can do something about it now.

Good point, thanks!
Maybe we can add a sanity check to be sure that only "allowed" layout names are used as keys for translations?
For example, we can collect all layout names used in cs.json "translations" section and make sure they correspond to a valid layout, using the "fonts" section keys: