IGemSorter should include FBP

[d-gs]

Feature request

Expected Behavior - What were you expecting to happen?

The extension to sort environments/projects should also allow to sort Feature Branch Providers (FBP) as there is no control on how are they are shown to the user for third-party tools.

Current Behavior - What happens?

The implementation of the sorter made on #18 is not complete in terms of what can be sorted by a third-party plug-in.

Possible Solution

Add a new method to the sorter and a default implementation (sort order by ID and/or name, but first the configured default provider).