Added Document Voting

[zenkimoto]

Closes #21

Description of Change

Added support for up/down voting and give reasons for the vote on the Google Documents detail view only.

Properties vote, voteDate and voteReason have been added to the Google DataStore Entity LibraryViewDoc.

EDIT: Updated with Stimulus

Motivation and Context

We want to keep track on which documents are helpful and which are not. We leverage the existing Google Datastore Entity as it is similar to a join table between users and documents.

Vote values are 1 for thumbs up and a -1 for thumbs down. The idea for using this is if we wanted to get the overall vote score of a document, we simply sum the votes.

Checklist

• [ ] Ran npm run lint and updated code style accordingly
• [ ] npm run test passes
• [ ] PR has a description and all contributors/stakeholder are noted/cc'ed
• [ ] tests are updated and/or added to cover new code
• [ ] relevant documentation is changed and/or added

[zenkimoto]

@gunsch - I will update this branch with the Stimulus stuff once this PR is approved and merged.