[FEAT]: Allow setting env settings from UI when importing compose

[TangentFoxy]

For example, when setting up PeerTube according to official documentation.

[azukaar]

Cosmos cannot support env files as-is because it does not use "files" to start composes The only thing that I could consider adding are setting fields when importing a compose with envs in them

[TangentFoxy]

As a first-step, could it import the values from the specified file? I know that might not just work because the env_file format gets preprocessed in some manner (something about how shells handle variables?), but having the skeleton - even with wrong values - would be easier than having to manually re-add variables. Especially when combined with a warning about that not working as expected.