* Work to unify log-file for agent/server and add rotation
* Updates to rotation code, tried to centralise the log config setup
* logging + tests
* Move LogFile to ShareConfig in test
* Docs
* Started work on adding log-file support to Agent
* Allow log file to be picked up and appended
* Use NewLogFile everywhere
* Tried to pull out the config aggregation from Agent.Run
Co-authored-by: Nick Cabatoff <ncabatoff@hashicorp.com>