[Feature] translate rich text blocks

[sargreal]

This adds experimental support for translating the blocks editor (fixes #401). The current implementation is very rudimentary.

Things to consider before merging:

• How to handle images better? The current way of creating a cache does not delete any images and may become a memory leak in large applications. But it is not clear when the cache may be deleted
• How to handle code better? In the current state, DeepL may just translate the code and in the process also remove any line breaks.
• Is it worth launching this feature in an experimental state, since we currently do not have the resources to fix bugs?

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 65.47619% with 29 lines in your changes are missing coverage. Please review.

Project coverage is 47.77%. Comparing base (0823a66) to head (3cb37ca).

Files	Patch %	Lines
plugin/server/services/format.js	68.57%	9 Missing and 13 partials :warning:
providers/deepl/lib/index.js	50.00%	2 Missing and 2 partials :warning:
providers/libretranslate/lib/index.js	50.00%	1 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #402 +/- ## ========================================== + Coverage 45.95% 47.77% +1.81% ========================================== Files 47 47 Lines 866 942 +76 Branches 187 211 +24 ========================================== + Hits 398 450 +52 - Misses 310 322 +12 - Partials 158 170 +12 ``` | [Flag](https://app.codecov.io/gh/Fekide/strapi-plugin-translate/pull/402/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fekide) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/Fekide/strapi-plugin-translate/pull/402/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fekide) | `47.77% <65.47%> (+1.81%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Fekide#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.