Rename channel_filter_* tables

* channel_filters is now river_channels and channel_filter_options
is now river_channel_options. These changes have also been
propagated to the POJO wiring and test data DML
Implement resources to modify channel and collaborators

* Wired in the service methods that implement the API
resources for modifying channels and collaborators. In the case of
modifying channels, the existing channel options (for the specified
channel) replaced with the ones specified in the payload.