Layered configuration with serde and figment

[slinkydeveloper]

Fix #53. Check #53 (comment) for more info about the behaviour.

[tillrohrmann]

Thanks for creating this PR @slinkydeveloper. The changes look good to me. +1 for merging.

A follow-up question I have is whether there is a way to automatically collect the configuration options and generate a list for documentation purposes. Ideally, we could also generate the corresponding env variable names for the different options.

[slinkydeveloper]

A follow-up question I have is whether there is a way to automatically collect the configuration options and generate a list for documentation purposes. Ideally, we could also generate the corresponding env variable names for the different options.

Ideally, we get rid of figment for that and directly build a macro ourselves to both generate a parser (also fixing the __ issue) and generate docs.

[tillrohrmann]

A follow-up question I have is whether there is a way to automatically collect the configuration options and generate a list for documentation purposes. Ideally, we could also generate the corresponding env variable names for the different options.

Ideally, we get rid of figment for that and directly build a macro ourselves to both generate a parser (also fixing the __ issue) and generate docs.

Sounds like an interesting follow-up idea.

[tillrohrmann]

LGTM. +1 for merging.