wip-feature: Allow resend of acceptance/rejection emails

[aviupadhyayula]

Creates an option for club admins to resend all acceptance/rejection emails, regardless of whether applicants have been previously notified or not. Resolves #585.

Still a WIP. To-do:

• Add tests
• Create stronger checks against people accidentally pressing this. Maybe we can add a pop-up or change the helpText to deter admins resending emails without good reason to. (CC'ing @julianweng)

What it looks like:

[rohangpta]

Can we get a review @julianweng @esinx @rm03? You can assign yourselves as reviewers on the top right and leave some comments where appropriate.

Would be lovely to get you all some practice with reviewing code :)

[esinx]

Looks good to me!
Might be an unrelated question, but are we somehow tracking which mails have been sent at what time? Might be useful to display a log of what mails have been sent through Penn Clubs.

[esinx]

@aviupadhyayula please feel free to merge whenever you feel comfortable about this PR!

[aviupadhyayula]

Might be an unrelated question, but are we somehow tracking which mails have been sent at what time? Might be useful to display a log of what mails have been sent through Penn Clubs.

Not that I know of, but this seems easy enough to implement. We could create a wrapper class around each email and append it to some global array. An alternative is using some package like django-mailer, which would store outgoing emails in a database.

Is there any reason we'd need this functionality? Can look into it with future PRs.