proxy: v2.110.0 (#4987)

This release fixes a recent regression in multicluster gateway
configurations that would forbid inbound gateway traffic. It also fixes
URI normalization for orig-proto-upgrade requests that do not include a
`Host` header.

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* http: Simplify stacks and target types (linkerd/linkerd2-proxy#656)
* Make SkipDetect more generic as stack::MakeSwitch (linkerd/linkerd2-proxy#657)
* introduce tests for isolated services (linkerd/linkerd2-proxy#655)
* http: Put normalize_uri back on the stack (linkerd/linkerd2-proxy#659)
* inbound: Apply loop detection on the connect stack (linkerd/linkerd2-proxy#660)
* tracing: Elide redundant info in tracing contexts (linkerd/linkerd2-proxy#661)
* outbound: Reorganize outbound stacks (linkerd/linkerd2-proxy#662)
* app: Decouple stacks from listeners (linkerd/linkerd2-proxy#663)
* inbound: Split HTTP detection stack from TLS (linkerd/linkerd2-proxy#664)
* integration: Bundle tests in src (linkerd/linkerd2-proxy#665)