Add configuration args to support domain rotation

[sysophost]

This adds the necessary args to support domain rotation for Websocket C2.

The changes in this PR break the existing implementation so should not be merged to main until other C2 agents have been updated to accommodate the changes.

• callback_host has been replaced with callback_hosts to enable storing multiple callback hosts
• domain_rotation_method, domain_rotation_delay, and domain_rotation_failure_threshold have been added to allow configuration of when to change hosts and maximum allowed failures per host.
• callback_port has been removed and is instead wrapped up within callback_hosts in the format ws[s]://domain[:port]
• endpoint replaces ENDPOINT_REPLACE and now expects a leading / (currently only a single endpoint is supported for all callback hosts)
• USER_AGENT and domain_front have been moved into the headers array to allow arbitrary headers to be set