We don't want to depend on the entire site configuration when we only
need a few specific settings.
This change additionally means that these services no longer see a live
version of the settings, but rather a copy. This means in tests you
really do have to call overrideMwServices() if you want services to pick
up your config changes.
ResourceLoader and SearchEngineConfig will need more work to port,
because they expose their member Config in a getter, and the getter is
actually used.
Parser and NamespaceInfo are also relatively complicated, so I split
them into separate patches.
Tested with 100% code coverage. \o/
Depends-On: If6534b18f6657ec1aba7327463f2661037f995b3
Change-Id: I1a3f358e8659b49de4502dc8216ecb6f35f4e02a
Introduce a service to represent wfReadOnly() and friends.
It's necessary to have two service instances, one for wfReadOnly() and
one for wfConfiguredReadOnlyReason(), to avoid a circular dependency,
since LoadBalancer needs the configured reason during construction, but
wfReadOnly() needs to query the currently active load balancer.
Not having a cache of the configuration makes it possible to dynamically
change the configuration. Ideally things would not change the
configuration, and I removed such instances in core, but to support
extensions, I added a test ensuring that the configuration can be changed.
Change-Id: I9bbee946c10742526d3423208efd68cb3cc5a7ee
