Improve manually upload files from git repo

[Misjohns]

Issue:
Currently a user enters Repo URL or Server Side File Path, Document name(s), and Commit SHA. This creates a lot of work for the user if there are multiple files within that repo; requires them to enter in every doc name separated by commas. With no typos.

Recommendation:
User should be able to enter a repo url then we display the list of all documents in that repo and let user select which they want to upload.