feat!: Add axum tooling to provide w3c tracecontexts in response payloads

[justinabrahms]

I'm not clear on which compiler flags we should expect observability.. but I assume all of them?

[github-actions]

Test flake analysis

status	platform	features	toolchain
🟢	ubuntu-latest	test-kubo,headers	stable
🟢	ubuntu-latest	test-kubo,headers,rocksdb	stable
🟡	macos-13	test-kubo,headers	stable
🟢	windows-latest	test-kubo,headers	stable
🟡	ubuntu-latest	test-kubo,headers	nightly
🟢	macos-13	test-kubo,headers,rocksdb	stable

Flake summary for macos-13, test-kubo,headers, stable

     Summary [  53.899s] 176 tests run: 176 passed (1 flaky), 1 skipped
   FLAKY 2/5 [  15.493s] noosphere::distributed_stress multiplayer::orb_can_render_peers_in_the_sphere_address_book

Flake summary for ubuntu-latest, test-kubo,headers, nightly

     Summary [  44.870s] 176 tests run: 176 passed (1 flaky), 1 skipped
   FLAKY 2/5 [  16.781s] noosphere::distributed_stress multiplayer::orb_can_render_peers_in_the_sphere_address_book

[jsantell]

Pushed a change that adds an on-by-default feature flag for enabling this in our two HTTP servers:

• Adds an observability flag to noosphere-cli (on by default) to toggle noosphere-gateway's otel capabilities.
• Same with noosphere-ns for orb-ns, enabled by default.