This PR adds the necessary resolvers to support
the graphQL front-end. Some additional methods
need to be added to the model structs to support
this. Comments have been made to clarify their purpose.
There is a slight duplication of code in the api layer.
But eventually that's going to go away when we move
away from the REST API entirely.
The schema is in api4/schema.graphqls and gets compiled
into the binary as an asset.
The GraphiQL editor url is at GET /api/v5/graphql.
Everything is behind the feature flag MM_FEATUREFLAGS_GRAPHQL.
```release-note
NONE
```
* Run all tests fasts in postgres
* Moving postgres config to a file
* Addressing PR review comments
* Testing against mysql in the CI to keep things less changed
* Revert "Testing against mysql in the CI to keep things less changed"
This reverts commit fc940c111db269a821c54e005d76df87cb70e031.
* Fixing a test broken in postgres but working in mysql
* Fixing some tests
* Fixing some config tests with postgres
* Fixing the rest of config tests
* Fixing govet error
* Fixing search tests for postgres
