Release v0.15.0

- Fixed uncaught exception when w/out tor (#2033)
- Importable module renamed to sherlock_project
- - Reference Debian 1072733
- Adopted Poetry, restructured as package
- Reworked regression testing (adopted pytest, tox)
- Returned schema specification to manifest
- Added detection for users running python3 sherlock
- Deprecated torrequest (warning message added)
- Deprecated Python 3.6 3.7 (now ^3.8)

Retroactive tag pushed for 0.15.0 interactive diff