add mTLS to TSA for sign-blob command

[dmitris]

Summary

Clone of #3052 but for the cosign sign-blob command.

Add command-line parameters for key/cert/cacert used for the connection to the TSA server to the sign-blob command.

Fixes #3006.

Release Note

• New features and improvements, including behavioural changes, UI changes and CLI changes
  ** Additional command-line options for cosign sign-blob command for mTLS connection to the TSA server

Documentation

sigstore/docs#239

[codecov]

Codecov Report

Merging #3200 (085208d) into main (1e9bac4) will decrease coverage by 0.09%.
Report is 2 commits behind head on main.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3200      +/-   ##
==========================================
- Coverage   30.42%   30.33%   -0.09%     
==========================================
  Files         155      155              
  Lines        9798     9827      +29     
==========================================
  Hits         2981     2981              
- Misses       6369     6398      +29     
  Partials      448      448              

Files Changed	Coverage Δ
cmd/cosign/cli/options/signblob.go	0.00% <0.00%> (ø)
cmd/cosign/cli/sign/sign_blob.go	0.00% <0.00%> (ø)
cmd/cosign/cli/signblob.go	0.00% <0.00%> (ø)

[haydentherapper]

Looks great!