Bind flags as prefixed env variables

[hectorj2f]

Signed-off-by: Hector Fernandez hector@chainguard.dev

Summary

There is an increase in the amount of flags used in our commands. Therefore we should think about binding these flags as environment variables that would help us when using the commands.

closes #2330

Release Note

Allow setting flag values via environment variables

Documentation

[codecov-commenter]

Codecov Report

Merging #2346 (88d16d7) into main (ef9cf9d) will decrease coverage by 0.16%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #2346      +/-   ##
==========================================
- Coverage   29.87%   29.70%   -0.17%     
==========================================
  Files         134      134              
  Lines        8289     8335      +46     
==========================================
  Hits         2476     2476              
- Misses       5482     5528      +46     
  Partials      331      331              

Impacted Files	Coverage Δ
cmd/cosign/cli/attach.go	0.00% <0.00%> (ø)
cmd/cosign/cli/attest.go	0.00% <0.00%> (ø)
cmd/cosign/cli/attest_blob.go	0.00% <0.00%> (ø)
cmd/cosign/cli/clean.go	0.00% <0.00%> (ø)
cmd/cosign/cli/completion.go	0.00% <0.00%> (ø)
cmd/cosign/cli/copy.go	0.00% <0.00%> (ø)
cmd/cosign/cli/dockerfile.go	0.00% <0.00%> (ø)
cmd/cosign/cli/download.go	0.00% <0.00%> (ø)
cmd/cosign/cli/generate.go	0.00% <0.00%> (ø)
cmd/cosign/cli/generate_key_pair.go	0.00% <0.00%> (ø)
... and 14 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[priyawadhwa]

This looks great @hectorj2f !!

[cpanato]

looks cool