Rename ResilienceStrategyBuilder to CompositeStrategyBuilder

[martintmk]

Details on the issue fix or feature implementation

Per discussion in #1233

• We don't want to use term "Pipeline" because it's not used anywhere in the public API.
• CompositeStrategyBuilder is good term because it indicates the result is composite strategy and has Strategy in the name.

Contributes to #1301

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 #1448 (f2e67e8) into main (a1b7a7f) will not change coverage.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1448   +/-   ##
=======================================
  Coverage   83.90%   83.90%           
=======================================
  Files         273      273           
  Lines        6516     6516           
  Branches     1012     1012           
=======================================
  Hits         5467     5467           
  Misses        840      840           
  Partials      209      209           

Flag	Coverage Δ
linux	83.90% <100.00%> (?)
macos	83.90% <100.00%> (ø)
windows	83.90% <100.00%> (ø)

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

Files Changed	Coverage Δ
...ircuitBreakerCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...Core/CircuitBreaker/CircuitBreakerStateProvider.cs	100.00% <ø> (ø)
src/Polly.Core/CompositeStrategyBuilder.cs	100.00% <ø> (ø)
...c/Polly.Core/CompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...back/FallbackCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...e/Retry/RetryCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...meout/TimeoutCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...try/TelemetryCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
...g/RateLimiterCompositeStrategyBuilderExtensions.cs	100.00% <ø> (ø)
src/Polly.Core/CompositeStrategyBuilder.TResult.cs	100.00% <100.00%> (ø)
... and 10 more