Multiple improvements and fixes

[alexkunde]

Hi, Im not sure if this repo is still being actively maintained, but if so, please see the following changes.

Changes

Breaking

• (maybe) breaking: updated exists() to check systemctl list-unit-files. Units can exists here, but not have a status

Features

• added unit_list_full() function which returns all three info columns from systemctl list-unit-files as a vector of structs. unit_list_full() now has the actually logic, with unit_list() reducing the result to a vector of strings with names.
• added glob filter to unit_list() and unit_list_full() so you can filter for unit names. e.g. systemctl list-unit-files cron* would only return units starting with cron
• added transient as a field for Unit struct, as it can appear
• add Cntrl PID option for PID

Fixes / Improvements

• updated dependencies
• updated edition to 2021
• removed default-env dependency, it's not needed and updated systemctl() and systemctl_capture() function with native env variables
• add test for unit_list_full()
• fix clippy warnings and deactive them for not-implemented parts
• re-do the whole default() thing, most of it can be derived and will save on code
• switch the Unit if...else to .strip_prefix(). It will return false if it doesnt work, or return back the value without prefix

[alexkunde]

@gwbres the pipeline is failing as per main branch. To fix it, we can revert e20fdfb (I did a fix to be able to test locally), but that is an architectural decision I would leave up to you
Alternatively we could add the missing variant to the Type enum and leave the code panicking whenever a type error appears.

[gwbres]

@alexkunde

Thank for the many improvements ! let's merge them we'll fix the pipeline later