Support document multiple instance and change doc_id from String to &str

[qinluhe]

Feature Preview

• Support multiple document instances
• Change doc_id from String to &str
• Support multiple menu to respond arrow key events
• Fixed emoji caret position
• Fixed paste didn't work bugs

---

PR Checklist

• My code adheres to the AppFlowy Style Guide
• I've listed at least one issue that this PR fixes in the description above.
• I've added a test(s) to validate changes in this PR, or this PR only contains semantic changes.
• All existing tests are passing.

[codecov]

Codecov Report

Merging #2808 (0ab4904) into main (d986e01) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #2808   +/-   ##
=======================================
  Coverage   57.33%   57.33%           
=======================================
  Files         401      401           
  Lines       18684    18684           
=======================================
  Hits        10712    10712           
  Misses       7972     7972           

Flag	Coverage Δ
appflowy_flutter_integrateion_test	54.97% <ø> (ø)
appflowy_flutter_unit_test	13.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.