R1:99c864f5e6fb

Provide a basic detail view for user activity logs

Summary:
Depends on D20673. Ref T13343. Since we're now putting log IDs in email, make the UI a little better for working with log IDs.

Some day, this page might have actions like "report this as suspicious" or whatever, but I'm not planning to do any of that for now.

Test Plan: {F6608631}

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13343

Differential Revision: https://secure.phabricator.com/D20674