refactor: File.optimize_file
refactor: File.optimize_file

* Generalize file content reverting on rollback
* Overwrite current file instead of adding a dangling new file
* Use File.save_file instead of additional "custom" logic
* Set File.content on calling get_content method

frappe/frappe,frappe/frappe,yashodhank/frappe,StrellaGroup/frappe,frappe/frappe,yashodhank/frappe,StrellaGroup/frappe,StrellaGroup/frappe,yashodhank/frappe,yashodhank/frappe