feat: support switch model

[Xazin]

Here's a clearer version of your message:

1. Support switching to other models. The local AI model will be completed in another PR.

2. Replace editor OpenAI calls with AppFlowy AI. For example, support improving writing with Claude-3-Sonnet or OpenAI.

3. Support enabling AI search (to be used in a future version).

4. Disable generating images from text. This issue will be fixed in another PR.

[github-actions]

🥷 Ninja i18n – 🛎️ Translations need to be updated

Project /project.inlang

lint rule	new reports	level	link
Missing translation	364	warning	contribute (via Fink 🐦)
Message without source	7	warning	contribute (via Fink 🐦)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.72%. Comparing base (94f9349) to head (9a3b43d).
Report is 826 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##            main    #5575       +/-   ##
==========================================
+ Coverage   9.70%   86.72%   +77.02%     
==========================================
  Files        685      219      -466     
  Lines      31812     5039    -26773     
  Branches       0      833      +833     
==========================================
+ Hits        3086     4370     +1284     
+ Misses     28726      562    -28164     
- Partials       0      107      +107     

Flag	Coverage Δ
appflowy_flutter_unit_test	?
appflowy_web_app	86.72% <ø> (?)

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