Extract ChannelType into ChannelWidget
Support sharing of ArchiveBrowser among channel types
Make channel widgets configurable from within yamcs-ui.yaml
Extend iipcs with acq&gen time

This is useful information to have when subscribing to the
ContainerRequestManager. (similar to content provided in
ParameterValues).
Channel: Swap order of PRM/CRM creation

I was in need of accesing the CRM from a
custom parameterProvider (instantiated via PRM).

One of these days a better solution would be more appropriate.
Too much stuff is happening inside the Channel constructor,
complicating the order of references between sub-components.
Rename channel.yaml and yamcs-ui.yaml to sample files

Makes it easier to have deployment-specific configuration
files in other RPMs
Merge pull request #46 from fqqb/next

New channel widget + misc