chore: Fork rs-ucan into noosphere-ucan and noosphere-ucan-key-support

[jsantell]

Bump internal version of ed25519-zebra to 4.

[github-actions[bot]]

Test flake analysis

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

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

     Summary [  63.758s] 208 tests run: 208 passed (1 flaky), 2 skipped
   FLAKY 2/5 [   8.024s] noosphere::distributed_basic synchronize_petnames_as_they_are_added_and_removed

[jsantell]

Rebased unsigned-varint collision with https://github.com/subconsciousnetwork/noosphere/pull/825

edit: more nightly lints popping up, changes from original ucan are:

• Bump MSRV to 1.75.0
• Replace ToString implementations with Display (in other noosphere-* as well)
• Derive Default implementation where possible rather than explicit impl Default (in other noosphere-* as well)

[jsantell]

Patching the latest nightly lints as well https://github.com/subconsciousnetwork/noosphere/actions/runs/7978793781/job/21784685442?pr=815