38 integrate palmyra with google drive api

[vulongphan]

This PR implements the following

• Allow uploading files to Google Drive (new files are created and existing files are updated)
• Enforce persistence for Google authentication (users do not have to authenticate the second time in the same session)
• Enable Google Drive file picker pop-up for retrieving uploaded files

[muhammed-abuodeh]

(commit 73b4f52) is it fine for the GCP_CLIENT_ID and GCP_API_KEY to be public (just making sure)?

[muhammed-abuodeh]

change #saveremote to #saveRemote

[muhammed-abuodeh]

saveremoteToggle() -> saveRemoteToggle
make sure naming is consistent

[vulongphan]

(commit 73b4f52) is it fine for the GCP_CLIENT_ID and GCP_API_KEY to be public (just making sure)?

Yes, I think this is not the best practice. A workaround would be to set environment variables in Github Page; and since I do not have access to the repo settings, we would need to work together on this