User should be able to optionally provide a commit message for the sync action with the external repository

Create a new build parameter (using an env variable or data.json) to enable/disable this behavior. If disabled, default commit messages are used. If enabled, a modal should appear for each Commit action.
Commits are done in multiple situations on KIE Sandbox (e.g. pushing, manually committing etc). Whenever a commit action is done, if this option is enabled, prompt users with a modal for them to write a custom commit message.
When this option is enabled, before committing with the user-defined custom message, the “Git commit validation service” should be queried to verify that the commit message is valid. If not, the commit cannot be done and users will be unable to execute operations that depend on commits on KIE Sandbox (e.g. “Commit” or “Push”).