Casaconfig

Adds a new NoNetwork exception and fixes 2 bugs in existing exception handling.

Build now uses pyproject.toml instead of setup.py. No other changes from 1.0.1.

Identical to v1.0.0, only internal changes relevant to creating test releases and unused documentation and data cleanup.

**Full Changelog**: https://github.com/casangi/casaconfig/compare/v1.0.0.1...v1.0.1-2

First release of casaconfig. To be used by CASA 6.6.4. See the casaconfig API in casadocs.

Nearly ready for validation testing.