Write user guide doc on how to apply to volunteer

[Mariatta]

Document and describe the volunteer application process.

1. Create a volunteer profile
2. Enter the required info, like language selection, discord username, etc
3. They'll receive an email
4. Team member will review pending applications
5. Accepted volunteers will be given access to necessary resources eg Discord role, GDrive, etc
6. They'll receive email communications in their primary email.

[manaalsyed]

i'm working on this