RFC: local server setup

[efahl]

Includes the documentation for setting up a local server, and all the code changes I've made to get container volumes to work. Added .env to containers, filtering it for values that are host-only.

Addresses https://github.com/openwrt/asu/issues/1002

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review.

Project coverage is 90.77%. Comparing base (5e65dec) to head (4b6c9a2). Report is 224 commits behind head on main.

Files with missing lines	Patch %	Lines
asu/build.py	81.81%	2 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1032       +/-   ##
===========================================
+ Coverage   80.75%   90.77%   +10.02%     
===========================================
  Files          15       14        -1     
  Lines         977     1117      +140     
===========================================
+ Hits          789     1014      +225     
+ Misses        188      103       -85     

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[efahl]

@aparcar, I know there's a ton of stuff mashed together here, but could you take a quick look at just the podman-compose.yml and see if you have any comments? I'm specifically interested in my changes to the volume mounts, where $PUBLIC_PATH is always the host-side value, and the container-side paths are always /app/public. Does that make sense on the production server?

This was the biggest stumbling block in getting my local server running, as the mounts either failed on the host or were wrong on the containers otherwise.

[aparcar]

Kindly check out the changes here https://github.com/openwrt/asu/pull/1253