Implements #1577, but the issue should remain open until we clean up
the debugging loglines.

Improve debuggability of some config deserialization errors

If history is disabled, disable the history CAPs

Fixes #1510

Track channel join times, use them to optionally enforce history access
restrictions

Improve auditability of sensitive operator actions

strip local_ from oper capab names, also consolidate unban into ban

Add the new utf8-only cap, disallow non-utf8 when websockets are enabled

Fixes #810

Tor listeners should never see an STS cap.

Add an undocumented 'hide-sts' key for listeners that hides the STS cap.
This can be used if the listener is secured at layer 3 or 4 (VPNs,
E2E mixnets). It will be necessary to add the relevant IPs to `secure-nets`.

Fixes #1407

Support PROXY protocol v2, including ahead of plaintext connections

See #1171.

Add chanmode preventing speech to error message.

Fixes #1182.

See #1240.

See discussion on #68.

These should have been removed in #1027.

Since allocating them is rare.