add ability for plugins to be fetched from authenticated URLs #6816

Job	Run time
Lint Rust	5m 45s
Build Spin Ubuntu	21m 21s
Build Spin (windows-latest)	30m 19s
Build Spin static (aarch64, aarch64-unknown-linux-musl)	16m 27s
Build Spin (macos-13)	15m 50s
Test Spin (ubuntu-22.04-4core-spin)	8m 26s
Build Spin static (amd64, x86_64-unknown-linux-musl)	15m 25s
Review new dependencies for known vulnerabilities	4s
Build Spin (macos-14)	13m 44s
Test Spin (macos-14)	26m 32s
Run release build steps (ubuntu-20.04, amd64, --features openssl/vendored, target/release)	15m 5s
all-integration-tests	23m 24s
Run release build steps (ubuntu-20.04, aarch64, --features openssl/vendored --target aarch64-unkn...	16m 13s
Run release build steps (macos-13, amd64, target/release)	17m 45s
Run release build steps (macos-14, aarch64, target/release)	11m 39s
Run release build steps (windows-latest, amd64, .exe, target/release)	26m 23s
	4h 24m 22s

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