Change to using environment variables in favor of CLI args

[kenkendk]

Update Docker images to use environment variables and add variables that guard against using a potentially volatile encryption key.

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• I have read the contributing guideline and understand that I have made the correct modifications

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Description:

The change is to remove the CLI args:

--webservice-interface=any --server-datafolder=/config --webservice-allowed-hostnames=* 

And move them into environment variables:

DUPLICATI__SERVER_DATAFOLDER=/config
DUPLICATI__WEBSERVICE_PORT=8200
DUPLICATI__WEBSERVICE_INTERFACE=any
DUPLICATI__WEBSERVICE_ALLOWED_HOSTNAMES=*

This was not possible before issue #5456 but makes it more Docker-like. Note that this means the Dockerfile here will not work with builds prior to 2.0.9.103, as it requires the cmdline args.

Additionally, this PR adds the two new settings related to settings encryption described in issue #5496:

DUPLICATI__DISABLE_DB_ENCRYPTION=true
DUPLICATI__REQUIRE_DB_ENCRYPTION_KEY=true

These two options and their motivation are described in #81 .
Applying these two options without the other changes is also possible and will have no effect until 2.0.9.105 is released.

Benefits of this PR and context:

This fixes #81 and makes management of Duplicati instances slightly easier.

How Has This Been Tested?

This has not been tested (not using the image myself), but replicates the Duplicati project Dockerfile.

Source / References:

Provided inline above, where relevant.

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[kenkendk]

This clashes a bit with #82 which was a slightly faster than me :)

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/duplicati/development-v2.0.9.104_canary_2024-08-21-pkg-eed53456-dev-0d6e23a3113d77476e49249cd42597be41e52e1e-pr-83/index.html
https://ci-tests.linuxserver.io/lspipepr/duplicati/development-v2.0.9.104_canary_2024-08-21-pkg-eed53456-dev-0d6e23a3113d77476e49249cd42597be41e52e1e-pr-83/shellcheck-result.xml

Tag	Passed
amd64-development-v2.0.9.104_canary_2024-08-21-pkg-eed53456-dev-0d6e23a3113d77476e49249cd42597be41e52e1e-pr-83	✅
arm64v8-development-v2.0.9.104_canary_2024-08-21-pkg-eed53456-dev-0d6e23a3113d77476e49249cd42597be41e52e1e-pr-83	✅