Read wsl-distribution.conf and wsl.conf from /usr/lib if not present in /etc

[septatrix]

Is your feature request related to a problem? Please describe.
Immutable/hermetic Distros may choose to only provide a /usr directory and mount other dirs like /etc as a tmpfs in which case it is not possible to ship the above config files in their original location

Describe the solution you'd like
WSL should fallback to reading the config from /usr if it cannot find it in /etc. Even better would be to merge the configs if both files are present

Describe alternatives you've considered
Do not support hermetic distros

Additional context
The most popular example of such a distro is likely the impermanence mode of NixOS but there many custom, specialized distros which go this route. E.g. most immutable distros only provide a /usr and only populate /etc upon first boot

[github-actions]

Logs are required for review from WSL team

If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
Otherwise please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

How to collect WSL logs

Download and execute collect-wsl-logs.ps1 in an administrative powershell prompt:

Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
Set-ExecutionPolicy Bypass -Scope Process -Force
.\collect-wsl-logs.ps1

The script will output the path of the log file once done.

If this is a networking issue, please use collect-networking-logs.ps1, following the instructions here

Once completed please upload the output files to this Github issue.

Click here for more info on logging
If you choose to email these logs instead of attaching to the bug, please send them to [email protected] with the number of the github issue in the subject, and in the message a link to your comment in the github issue and reply with '/emailed-logs'.

[septatrix]

/feature

[github-actions]

Diagnostic information

Found '/feature', adding tag 'feature'