Add the option to check for obsolete dev-dependencies about deptry

[fpgmaas]

For now added the wontfix label, since this will be quite a large overhaul, and I am wondering if user configuration won't become too confusing. Users would need to specify separately which files and directories to include for both the regular and the development dependency checks.

On the other hand, most of the required classes and functions are already there. Optionally we could add a separate command, so users could run:

deptry .

to check regular dependencies and

deptry dev .

To check the development dependencies.

Anyway, if this issue gains attention in the future, we could always reconsider.