Details on the issue fix or feature implementation

This change simplifies the API and allows listening to multiple reload tokens.

Essentially, the caller can now do:

services.AddResiliencePipeline("my-pipeline", (builder, context) =>
{
    context.EnableReloads<Options1>();
    context.EnableReloads<Options2>();
   
    // add strategies
});

Whenever Options1 or Options2 are changed, the pipeline is reloaded. Previously, the pipeline could listen only to a single options.

Enabled by #1511
Contributes to #1507

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• 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