953 remove strand in batch

[rayzhuca]

Fixes batch delete/set labels and names for domains and strands.

Description

• Used BatchAction to group together set labels/name.
• Created get_selected_domains function that returns a BuiltSet<Domain> set, so setting domain names still work if
  user selects with domain tool
• Renamed some functions like set_substrand_names to set_domain_names.

[dave-doty]

This is a good start, but it should also work for extensions and loopouts. For example, if I select these two extensions and select "Remove extension name":

it should remove both names, but still removes only one.

If you notice, the original function names talked about substrands rather than domains. I named them that way to make the code generally useful for all three types of substrands (Domain, Extension, and Loopout). Although maybe they weren't being used in the latter two cases, but nevertheless there should be some way (without too much copy-pasting of code) to make this work for all three cases.

[dave-doty]

I think this should say "remove strand name" instead of "remove strand label"