config option to selectively ignore some incoming URLs

[trentm]

This issue is to add an equivalent to transaction_ignore_urls, and also to make it dynamically configurable via central config.

The intent is to implement this using a ComposableRuleBased sampler, so this depends on #1046 being implemented first.

[trentm]

See Sylvain's for Java for this: elastic/elastic-otel-java#900

[trentm]

Blocked by #1046

[trentm]

Blocked on having declaractive config to expose configuration for this: possibly open-telemetry/opentelemetry-js#6506 if that includes the full sampler config, e.g. as at https://github.com/open-telemetry/opentelemetry-configuration/blob/63c40f04b73c7fee0296f4aefe2958877ed69826/snippets/Sampler_rule_based_kitchen_sink.yaml

Users can manually use the Composable samplers to build this functioanlity up. Having an example/doc for that would be useful.