Sentinel-Minipots version 2.2

Added
* ipeline integration tests
* Doc comments
* Throughput integration tests
* Logging

Removed
* anual proxy - moved to Proxy repo
* Minipots doc - moved to internal wiki

Changed
* Update README
* Update integration tests doc
* Update Minipots doc
* Send invalid Sentinel message if missing username
* HTTP minipot - limit announced version
* HTTP minipot - make user agent optional part of Sentinel message

Fixed
* Debug prints
* HTTP content length parsing
* SMTP SASL mechanism field name