R1:580409b5628d

Modularize Almanac Network transactions

Summary: Depends on D19321. Ref T13120. Ref T12414. Move transactions for Almanac Networks (just "name") to ModularTransactions.

Test Plan:
- Created a new network.
- Renamed a network.
- Tried to create a network with no name (got an error).
- Grepped for `AlmanacNetworkTransaction::`.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13120, T12414

Differential Revision: https://secure.phabricator.com/D19322