Add an option for mono mic capture in ZoomIt

[foxmsft]

Summary of the Pull Request

There are sound cards that expose groups of inputs for their microphone inputs. Added that option here, and normalizing their audio samples if checked (division by sqrt).

PR Checklist

• Closes: #xxx

• Communication: I've discussed this with core contributors already. If the work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end-user-facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[foxmsft]

The option looks like this:

In standalone (not really relevant here):

The rationale (on my machine), notice that there are 2 channels with different microphones for the recording, causing the audio to be fully panned to a side: