[BUG] [SECURITY] Password of emailaccount is plaintext and visible #1233

Describe the bug
The password of the account to access the mailbox is visible in plaintext in the webinterface (and therefore also in the database)

To Reproduce
Steps to reproduce the behavior:

1. Go to '/admin/paperless_mail/mailaccount/1/change/'
2. Scroll down to 'Password'
3. See error

Expected behavior
A hidden/obscured representation (all asterisks or something)
And also stored as a hash in the database.

Screenshots
I do not think so ;)

Webserver logs

Irrelevant

Relevant information

• Host OS of the machine running paperless: [e.g. Archlinux / Ubuntu 20.04]
• Browser [e.g. chrome, safari]
• Version [e.g. 1.0.0]
• Installation method: [docker / bare metal]
• Any configuration changes you made in docker-compose.yml, docker-compose.env or paperless.conf.