Add commit message from plugin

[lukasoppermann]

It would be great if the user could add a commit message when sending the file to the server. Ideally this would include a version number as well #69

What would be neat:

• [ ] turn server settings into a settings only page
• [ ] add a send to server command that opens a dialog with the following options
  • [ ] Version Number pre-filled with last version
  • [ ] Title
  • [x] Description
  • [ ] Checkbox for "also save as figma history version" (which needs to store the state)
• [ ] all properties (apart from the version) should be send via the client_payload to the server
• [ ] if the checkbox is active a new versionHistory should be written with
  • title: Version (if provided) + title
  • description: Commit Message