WIP: Enable Non-Root Runner Scenarios

[JustinGrote]

Currently act requires the docker container to have root privileges to work because it both binds and mounts to the "same path" as the host.

While the bind method is useful if using act as a task runner, the mount method will fail in non-root containers.

In order to more accurately test Github Actions for both permission and pathing errors, this PR makes mounts use the runner workdir by default and sets permissions accordingly. Binds with the -b flag will be unaffected and will continue to use the same path as what is on the container.

It will also add a parameter to customize the starting container workdir separately from the host workdir, if there is such a situation where you dont' want to use the default (usually /home/runner/workdir)

Example that this will fix

Try a simple action that does mkdir -p /my/random/path. This will work just fine in act, but fail in Github Actions, and you won't find out till you run it in github actions.

[mergify]

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[catthehacker]

There is quite a mix of old code and different branches from your fork

[JustinGrote]

@catthehacker yeah as mentioned it's draft and WIP, I just rebased to my ActForWindows branch and haven't cleaned up the stuff that the merge missed.

[mergify]

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[codecov]

Codecov Report

Merging #666 (42b0385) into master (0f04942) will increase coverage by 0.84%.
The diff coverage is 58.13%.

@@            Coverage Diff             @@
##           master     #666      +/-   ##
==========================================
+ Coverage   49.27%   50.11%   +0.84%     
==========================================
  Files          23       23              
  Lines        2401     2542     +141     
==========================================
+ Hits         1183     1274      +91     
- Misses       1090     1132      +42     
- Partials      128      136       +8     

Impacted Files	Coverage Δ
pkg/container/docker_run.go	1.74% <0.00%> (-0.19%)	⬇️
pkg/common/git.go	54.67% <33.92%> (-5.12%)	⬇️
pkg/model/planner.go	34.56% <41.37%> (+1.48%)	⬆️
pkg/model/workflow.go	30.71% <60.00%> (+5.00%)	⬆️
pkg/container/docker_pull.go	36.17% <64.70%> (+17.98%)	⬆️
pkg/runner/step_context.go	73.00% <74.79%> (+4.05%)	⬆️
pkg/runner/run_context.go	79.74% <94.82%> (+3.33%)	⬆️
pkg/runner/runner.go	76.92% <100.00%> (+0.45%)	⬆️
... and 1 more

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[mergify]

@JustinGrote this pull request has failed checks 🛠

[JustinGrote]

Requesting design review and that you agree with the approach before I finish tests.
@catthehacker @cplee ping for review, thanks :)

[mergify]

@JustinGrote this pull request is now in conflict 😩

[github-actions]

PR is stale and will be closed in 14 days unless there is new activity