New feature selection

It would be very convenient to get a list of plugins and their blocks and show if the block(s) for the plugin are used or not. This would help identify if all blocks for a plugin are not used so we could remove the plugin. Certain plugins (example spectra) have an interface to enable or disable the use of a block but most of them do not. It is tedious (and prone to mistakes) to identify if a plugin actually used or not.