Adjustable preview sizes

[tvdeyen]

What is this pull request for?

You are now able to configure preview sizes in the alchemy/config.yml file.

page_preview_sizes:
  - 360
  - 640
  - 768
  - 1024
  - 1280
  - 1440

and adjust them to your breakpoints. Translate the value with alchemy.preview_sizes.<value> in your locale file.

Notable changes

Use normal select for preview sizes

Screenshots

Checklist

• [x] I have followed Pull Request guidelines
• [x] I have added a detailed description into each commit message
• [ ] I have added tests to cover this change

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.97%. Comparing base (efb901e) to head (f055396).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2923 +/- ## ======================================= Coverage 95.97% 95.97% ======================================= Files 232 232 Lines 6279 6280 +1 ======================================= + Hits 6026 6027 +1 Misses 253 253 ```

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