Enhancements on Helix.Websocket.Join

[renatomassaro]

Also includes some enhancements on ChannelHenforcer and ServerHenforcer.

Incidental:

• Add NetworkHenforcer

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This change is 

[sourcelevel-bot[bot]]

Ebert has finished reviewing this Pull Request and has found:

• 3 possible new issues (including those that may have been commented here).
• 4 fixed issues! 🎉

You can see more details about this review at https://ebertapp.io/github/HackerExperience/Helix/pulls/312.

[renatomassaro]

Reviewed 14 of 14 files at r1. Review status: all files reviewed at latest revision, all discussions resolved.

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