Replace transfer list on email page with member selector

[pieperm]

Is your feature request related to a problem? Please describe.
The Email page currently uses a transfer list for selecting recipients, which is not space-efficient and not mobile-friendly.

Describe the solution you'd like
A new component has been created for selecting members, MemberSelector, that addresses these issues. After replacement, recipient selection should retain the same capabilities. Additionally, the MemberSelector will need to be modified to include a button for exporting selected members to a CSV file. This should be configurable by a prop passed to the component.

Describe alternatives you've considered
None

Additional context
Related to issue #2111 and pull request #2170