foundationdb 7.x supports CMake & Ninja directly, and this
fork has significant FreeBSD improvements. This port allows users to
further validate and improve the port with various client libraries,
without needing to build FoundationDB entirely from scratch each time.

It depends on the preceding https://reviews.freebsd.org/D23278 for
mono as a build-time only dependency.

To Do:

test and add OPTIONS for
- [ ] Build Java Bindings                  OFF
- [ ] Build with TLS support               OFF
- [ ] Build Go bindings                    OFF
- [ ] Build Ruby bindings                  OFF
- [ ] Build Python sdist (make package)    ON
- [ ] Build Documentation (make html)      OFF
- [ ] Test upstream JavaScript bindings    PORT
- [x] Test upstream erlang bindings        PORT

This port already passes 100% of FoundationDB quick tests, and 97% of all tests, so
I'd like to commit it "as is" to enable wider testing by the FoundationDB community.

I believe that a large portion of this diff may have been derived from vanilla's
existing 6.x port, if so I will ensure the final PR gives credit & any license
/copyright attributions.