Deprecate server-side browsing of Google Drive files using the Google Picker API

[jrgriffiniii]

This follows samvera-deprecated/browse-everything-redux-react#27, as this would ensure that the Rails server mounting BrowseEverything is no longer involved in mediating asynchronous requests to the Google Drive API.

[jrgriffiniii]

I've been advancing this on a branch, and I do have this so that currently one is able to browse the contents of one's own Google Drive:

There are two possible problems which I've encountered thus far:

http://localhost:3001 cannot be used as a whitelisted origin for the Google Picker API. I have no idea why this is the case, but unless this is somehow related to my own account settings (I don't recall ever having used 3001 on any test applications before, but I may just not be remembering these cases correctly), then we may need to have the UI default to 3333 or something more obscure.

Also, as one can see, the Picker UI is a modal dialogue. I have no strong opinions on this, but the penalty from a design standpoint is there.

[jrgriffiniii]

I'm also seeing some 500 errors when requesting thumbnails or metadata:

[jrgriffiniii]

This is working for me locally with samvera-deprecated/browse-everything-redux-react@master...jrgriffiniii:issues-319-jrgriffiniii-google-filepicker and 2.x-stable...jrgriffiniii:issues-319-jrgriffiniii-google-picker.

However, there are improvements I would like to introduce to the React UI, along with integration testing I would like to undertake with https://github.com/pulibrary/figgy