Adding support for project as a directory of rulesets

[jhnwllr]

https://github.com/gbif/occurrence-annotation/issues/22

• Projects are now a directory of rulesets.
• When projects are deleted associated rules and rulesets are logically deleted.
• Tests added.
• Update README to reflect changes.

[timrobertson100]

Nice John!

I'll add that repository to the pom itself, to avoid people having to change maven settings.