llm-factor: migrate to `candle` #6655

Job	Run time
Review new dependencies for known vulnerabilities	12s
Build Spin static (aarch64, aarch64-unknown-linux-musl)	12m 39s
all-integration-tests	22m 46s
Build Spin static (amd64, x86_64-unknown-linux-musl)	12m 21s
Build Spin Ubuntu	11m 52s
Build Spin (windows-latest)	1m 42s
Build Spin (macos-13)	1m 43s
Run release build steps (ubuntu-20.04, amd64, --features openssl/vendored, target/release)	9m 17s
Lint Rust	2m 37s
Build Spin (macos-14)	1m 39s
Test Spin (ubuntu-22.04-4core-spin)	1m 1s
Run release build steps (ubuntu-20.04, aarch64, --features openssl/vendored --target aarch64-unkn...	9m 16s
Run release build steps (macos-13, amd64, target/release)	9m 17s
Test Spin (macos-14)	2m 43s
Run release build steps (macos-14, aarch64, target/release)	8m 59s
Run release build steps (windows-latest, amd64, .exe, target/release)	9m 8s
	1h 57m 12s

Provide feedback