feat: save context between calls

[TerryHowe]

What this PR does / why we need it:

This change saves authentication cache between calls so ORAS go scripting will auth once for most usages.

I created a test application to functional test this and it only authenticates the once.

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.19%. Comparing base (f6efe48) to head (d63287c).
⚠️ Report is 18 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/oras/internal/option/remote.go	80.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1923      +/-   ##
==========================================
+ Coverage   87.14%   87.19%   +0.04%     
==========================================
  Files         143      143              
  Lines        5540     5559      +19     
==========================================
+ Hits         4828     4847      +19     
  Misses        425      425              
  Partials      287      287              

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[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 30 days.