feat: Admin Email Page

[nightknighto]

Describe the solution you'd like

We need an email page in the admin section to be able to send mass emails to our participants.

Generally, the page should be like:
1- An input to write the body of the email.
2- Can select the tracks we want to send to. Can select 1 or more track.
3- Can select the participants' status we want to send to. Can select 1 or more status.
4- Can optionally select a new status to put all the emailed participants' status to after it is done.

Example #1: We want to send a rejection email to all participants in the AVR & ARM track whose status is rejected.

Example #2: We want to send an interview scheduling email to all participants of Web & Python tracks who has their status as pending, and we want to change their status to emailed after emailing them.