GitHub integration

[rvyuha]

Pushing functions for github interactions. Following changes were made:

• DESCRIPTION: Modified with 2 new packages for git interactions.
• create_release_files: Moved the stop(currently warning) to the main function to aid with flow.
• create_release_files: Added repo selection and branch creation to the main function body.
• validate_and_parse_files_sheet: Added a return for the error flag to be used in main body rather then this helper function.
• remove_files: Updated the path to reflect updates made in file creation.
• commit_files: Added a new helper function responsible for staging, committing, and pushing the changes to the new branch.

[rvyuha]

Pulled in changes from fork branch.