Remove env specifiers in settings

[aeshub]

Describe the improvement you would like to see
Remove the specification of env for every setting as these are redundant, it will default to the same name as the setting.

In addition, add a prefix FLOTILLA_ the same way as has been done in ISAR.

How will this change existing functionality?
Check that environment variable that may be passed in through docker-compose will still adhere to the correct prefix.

How will this improvement affect the current Threat Model?
Not affected.