Implement BIP159 NODE_NETWORK_LIMITED (pruned peers) *signaling only*

Summary:

Does implement BIP159, but only the signalling part. No connections are
made to NODE_NETWORK_LIMITED in this PR.

Backport of core PR11740

Depends on D2362

Test Plan:

./test/functional/test_runner.py node_network_limited

Reviewers: #bitcoin_abc, deadalnix, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: jasonbcox, teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2363