Encrypt on suspend

## Prerequisites
- [x] I have searched open and closed issues for duplicates.

## Feature
**Is your feature request related to a problem? Please describe.**
"hard disk encryption only protects user's data when their machine is shut down"

**Describe the solution you'd like**
"When you close the lid of your notebook, it goes into sleep/suspend mode. All processes are frozen and don't need to access your hard disk anymore. We use this opportunity to clean the keys of your encrypted devices and suspend them as well. Therefore, the data on your hard drive is protected. When resuming your computer, you must re-enter the password of your encrypted volumes. But then you're just where you've been working before."

I'm not sure if the Switchboard Power Plug is the right place for this feature request.
It's also possible to combine it with a new Encryption Pane.
I'm just thinking of a simple on/off switch in the Power Plug settings.
Of course it should also be possible to unlock with a Nitrokey if the "Close lid to encrypt" option is activated.

**Existing work**
please take a look a https://fosdem.org/2020/schedule/event/dip_close_lid_encrypt/
The above quotations for problem description and problem solution also come from this source.