Add "Content type" and "Rule type" fields to Herald rules for Herald rules

Summary:
Depends on D19400. Ref T13130. Currently, when you write Herald rules about other Herald rules, you can't pick a rule type or content type, so there's no way to get notified about edits to just global rules (which is the primary driving use case).

Add a "Content type" field to let the rule match rules that affect revisions, tasks, commits, etc.

Add a "Rule type" field to let the rule match global, personal, or object rules.

Test Plan:

• Wrote a global rule for other rules about global Herald rules:

{F5540307}

{F5540308}

• Ran it against itself which matched:

{F5540309}

• Ran it against another rule (not a global rule about Herald rules), which did not match:

{F5540311}

• Also reviewed the fields in those transcripts in more detail to make sure they were extracting matching correctly.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13130

Differential Revision: https://secure.phabricator.com/D19403