Summary:
Adds a new Support Grist page (accessible only in grist-core), containing
options to opt in to telemetry and sponsor Grist Labs on GitHub.
A nudge is also shown in the doc menu, which can be collapsed or permanently
dismissed.
Test Plan: Browser and server tests.
Reviewers: paulfitz, dsagal
Reviewed By: paulfitz
Subscribers: jarek, dsagal
Differential Revision: https://phab.getgrist.com/D3926
Summary: For grist-ee, expect an activation key in environment variable `GRIST_ACTIVATION` or in a file pointed to by `GRIST_ACTIVATION_FILE`. In absence of key, start a 30-day trial, during which a banner is shown. Once trial expires, installation goes into document-read-only mode.
Test Plan: added a test
Reviewers: dsagal
Reviewed By: dsagal
Subscribers: jarek
Differential Revision: https://phab.getgrist.com/D3426
