Move `HandlerType` to `spin-http` #6736

Job	Run time
Build Spin Ubuntu	22m 5s
all-integration-tests	25m 52s
Build Spin (windows-latest)	54m 38s
Build Spin static (aarch64, aarch64-unknown-linux-musl)	16m 44s
Build Spin (macos-13)	36m 59s
Build Spin static (amd64, x86_64-unknown-linux-musl)	16m 17s
Build Spin (macos-14)	22m 36s
Review new dependencies for known vulnerabilities	4s
Run release build steps (ubuntu-20.04, amd64, --features openssl/vendored, target/release)	15m 7s
Run release build steps (ubuntu-20.04, aarch64, --features openssl/vendored --target aarch64-unkn...	17m 42s
Lint Rust	9m 30s
Test Spin (ubuntu-22.04-4core-spin)	15m 1s
Run release build steps (macos-13, amd64, target/release)	19m 16s
Test Spin (macos-14)	52m 10s
Run release build steps (macos-14, aarch64, target/release)	13m 28s
Run release build steps (windows-latest, amd64, .exe, target/release)	27m 12s
	6h 4m 41s

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