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