[VAULT-28010] fix(funcs): fix relative paths in file()

[ryancragun]

The recently added file() function supports relative paths but they’ll always be relative to the working dir that exec’s enos. This is usually fine unless enos is invoked with --chdir, in which case we need funcs that support relative paths to be relative to the --chdir working dir.

• Make file() support the --chdir base path when given a base path
• Bump the version
• Add tests for funcs that support relative paths
• Remove test data that wasn't being used

Checklist

• The commit message includes an explanation of the changes
• Manual validation of the changes have been performed (if possible)
• New or modified code has requisite test coverage (if possible)
• I have performed a self-review of the changes
• I have made necessary changes and/or pull requests for documentation
• I have written useful comments in the code