Initial pkglistgen bot for Leap16

[lkocman]

• For now let's just make sure we can generate ftp-trees
• It's based on the existing LeapMicro pipeline

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (db6249f) 28.46% compared to head (91fe3fc) 28.46%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2939 +/- ## ======================================= Coverage 28.46% 28.46% ======================================= Files 84 84 Lines 14512 14512 ======================================= Hits 4131 4131 Misses 10381 10381 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openSUSE). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openSUSE)

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[nilxam]

OTOH you need some pkglistgen default attributes to be set for 16.0 otherwise it won't work porperly, you can copy them from https://build.opensuse.org/attribs/openSUSE:Leap:15.5 , see OSRT:Config

[lkocman]

Initial OSRT config https://build.opensuse.org/attribs/openSUSE:Leap:16.0

Variables taken from SUSE:ALP and substituted with our values from 15.5 as suggested above.

[nilxam]

https://github.com/openSUSE/openSUSE-release-tools/actions/runs/4373395463/jobs/7651517494

[lkocman]

https://github.com/openSUSE/openSUSE-release-tools/actions/runs/4373395463/jobs/7651517494

Fixed