Introduce ResilienceProperties

[martintmk]

The issue or feature being addressed

The resilience properties are heavily inspired by HttpRequestOptions and allow type-safe access to custom data attached to ResilienceContext.

Example Usage:

        var context = ResilienceContext.Get();
        var key = new ResiliencePropertyKey<string>("my-key");

        // set property
        context.Properties.Set(key, "my-value");

        // retrieve
        context.Properties.TryGetValue(key, out var value);

        // retrieve with the default fallback
        value = context.Properties.GetValue(key, "default-value");

Details on the issue fix or feature implementation

The ResilienceProperty are convertible to IDictionary<string, object?> and support the same scenarios as the Context found in V7. In general, extensibility author can expose well-known properties for easy and type-safe access.

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