Move pipeline-related internals into Pipeline folder

[martintmk]

Details on the issue fix or feature implementation

Internal only changes. To improve organization the pipeline-related APIs have been moved to PipelineFolder.
I have also introduced the static PipelineComponentFactory that creates pipeline components.

No other changes to files, shame that git is unable to match these changes as renames.

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 #1497 (8ed97f1) into main (149ed82) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1497      +/-   ##
==========================================
- Coverage   83.88%   83.88%   -0.01%     
==========================================
  Files         269      273       +4     
  Lines        6492     6491       -1     
  Branches     1024     1024              
==========================================
- Hits         5446     5445       -1     
  Misses        837      837              
  Partials      209      209              

Flag	Coverage Δ
macos	83.88% <100.00%> (-0.01%)	⬇️
windows	83.88% <100.00%> (-0.01%)	⬇️

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

Files Changed	Coverage Δ
src/Polly.Core/ResiliencePipeline.cs	100.00% <ø> (ø)
src/Polly.Core/ResiliencePipelineT.cs	100.00% <ø> (ø)
...olly.Core/Utils/Pipeline/ComponentDisposeHelper.cs	100.00% <ø> (ø)
.../Polly.Core/Registry/ResiliencePipelineRegistry.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResiliencePipeline.Async.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResiliencePipeline.AsyncT.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResiliencePipeline.Sync.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResiliencePipeline.SyncT.cs	100.00% <100.00%> (ø)
src/Polly.Core/ResiliencePipelineBuilderBase.cs	100.00% <100.00%> (ø)
.../Polly.Core/ResiliencePipelineBuilderExtensions.cs	100.00% <100.00%> (ø)
... and 9 more