Improve Herald personal/global UI/UX

Summary:

• Default "personal" vs "global" choice to "personal".
• Don't show global rules under "My Rules".
• After editing or creating a global rule, redirect back to global rule list.
• Use radio buttons for "personal" vs "global" and add captions explaining the

difference.

• For "global" rules, don't show the owner/author in the rule detail view --

they effectively have no owner (see also D1387).

• For "global" rules, don't show the owner/author in the rule list view, as

above.

• For admin views, show rule type (global vs personal).

Test Plan:

• Created and edited new global and personal rules.
• Viewed "my", "global" and "admin" views.

Reviewers: btrahan, jungejason, nh, xela

Reviewed By: btrahan

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1518