Remove use of os.Chdir

[phillebaba]

Describe what should be investigated or refactored

There are a couple of places in the code base where os.Chdir is used to access files in specific paths. Change of working directory is done temporarily in a function. Usually in the function the working directory is changed back in a deferred function. This is not a thread safe operation as setting the working directory is a per process system call. Packager and other components should support being used in multiple goroutines. For this reason we need to remove any use of os.Chdir.

Links to any relevant code

https://github.com/defenseunicorns/zarf/blob/601a282c78701bb039924c6c72802690656395df/src/pkg/packager/publish.go#L51
https://github.com/defenseunicorns/zarf/blob/601a282c78701bb039924c6c72802690656395df/src/pkg/packager/dev.go#L37

Additional context

N/A