Threepid seems to be pretty out of date, several missing endpoints.
Should also fix#3037, where we were still listening on the `/unstable`
prefix, while Element Web uses `/r0`
* Initial pass at refactoring config (not finished)
* Don't forget current state and EDU servers
* More shifting around
* Update server key API tests
* Fix roomserver test
* Fix more tests
* Further tweaks
* Fix current state server test (sort of)
* Maybe fix appservices
* Fix client API test
* Include database connection string in database options
* Fix sync API build
* Update config test
* Fix unit tests
* Fix federation sender build
* Fix gobind build
* Set Listen address for all services in HTTP monolith mode
* Validate config, reinstate appservice derived in directory, tweaks
* Tweak federation API test
* Set MaxOpenConnections/MaxIdleConnections to previous values
* Update generate-config
* Pass cfg by reference around the codebase
* Merge branch 'master' into pass-cfg-by-ref
Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
