* update tracing config definitions
* new tracing system
* performance improvements
* only configure tracing in envoy if it is enabled in pomerium
* [tracing] refactor to use custom extension for trace id editing (#5420)
refactor to use custom extension for trace id editing
* set default tracing sample rate to 1.0
* fix proxy service http middleware
* improve some existing auth related traces
* test fixes
* bump envoyproxy/go-control-plane
* code cleanup
* test fixes
* Fix missing spans for well-known endpoints
* import extension apis from pomerium/envoy-custom
This also replaces instances where we manually write "return ctx.Err()"
with "return context.Cause(ctx)" which is functionally identical, but
will also correctly propagate cause errors if present.
