ResilienceContextPool improvements

[martintmk]

Details on the issue fix or feature implementation

• This change allows us to make the ResilienceContext.ContinueOnCapturedContext property read-only.
• Introduced ResilienceContextCreationArguments so we can add more members to it in the future without breaking changes.

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[codecov]

Codecov Report

Merging #1493 (7b3b9d6) into main (e5622c0) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1493      +/-   ##
==========================================
+ Coverage   83.61%   83.64%   +0.02%     
==========================================
  Files         267      268       +1     
  Lines        6385     6394       +9     
  Branches     1007     1007              
==========================================
+ Hits         5339     5348       +9     
  Misses        837      837              
  Partials      209      209              

Flag	Coverage Δ
linux	83.64% <100.00%> (+0.02%)	⬆️
macos	83.64% <100.00%> (+0.02%)	⬆️
windows	83.64% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/Polly.Core/ResilienceContext.cs	100.00% <100.00%> (ø)
...c/Polly.Core/ResilienceContextCreationArguments.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResilienceContextPool.Shared.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResilienceContextPool.cs	100.00% <100.00%> (ø)
...lly/Utilities/Wrappers/ResilienceContextFactory.cs	100.00% <100.00%> (ø)

[martincostello]

Would be interesting to see if this has any effect on the benchmark results.