Add custom keymaps for other IDE flavors - Rider

[ckob]

I create this PR as a discussion about how could we add custom mappings needed per each IDE flavor.

For example, in Rider, the RenameFile action does nothing. But the RiderRenameFile does what's expected. I suppose the same could happen with other IDEA flavors.

Please feel free to propose or edit the PR with other code organization.

There could be several options, such as:

if is_ide_rider
  the Rider map
else
  the default map
endif

if is_ide_rider
   all the maps for rider together in a single if block, after the common ones
endif

Somehow a function where you pass on the map, default action name, rider action name, etc.

I opted to propose it with the inline-if, as it is close to the default mapping. And it adds just one line per each one.

[cufarvid]

Thanks for this PR!

I like keeping override mappings close to their originals as you've done. Makes perfect sense for maintenance. The inline-if approach works well enough for the Rider actions for now.

We've had some discussions about restructuring the project to make it a bit more modular (intellimacs has an interesting approach), but I don't have bandwidth for that kind of refactoring at the moment.

We can go with your solution for now - it solves the immediate problem without requiring a major overhaul. Before I merge, @mikeslattery - any thoughts on this?

Cheers for the contribution!

[mikeslattery]

@cufarvid, I like it.