Simplified PeekReader for MAVLink and made it `no_std` friendly #450

Job	Run time
linting	1m 51s
mavlink-dump	1m 1s
formatting	14s
internal-tests (ardupilotmega)	1m 12s
internal-tests (asluav)	1m 27s
msrv	2m 58s
internal-tests (matrixpilot)	1m 24s
internal-tests (minimal)	1m 28s
internal-tests (paparazzi)	1m 32s
internal-tests (python_array_test)	1m 25s
internal-tests (slugs)	1m 12s
internal-tests (standard)	1m 11s
internal-tests (test)	1m 15s
internal-tests (ualberta)	1m 39s
internal-tests (uavionix)	1m 15s
internal-tests (icarous)	1m 17s
internal-tests (common)	1m 9s
docs	44s
build (macos-latest, x86_64-apple-darwin, --features ardupilotmega)	3m 28s
build (ubuntu-latest, arm-unknown-linux-musleabihf, --features ardupilotmega)	2m 13s
build (ubuntu-latest, armv7-unknown-linux-musleabihf, --features ardupilotmega)	2m 14s
build (ubuntu-latest, x86_64-unknown-linux-musl, --features ardupilotmega)	2m 22s
build (ubuntu-latest, x86_64-unknown-linux-musl, --features ardupilotmega,emit-description,emit-e...	2m 22s
build (ubuntu-latest, thumbv7m-none-eabi, --no-default-features --features embedded)	1m 24s
build (windows-latest, x86_64-pc-windows-msvc, --features ardupilotmega)	3m 22s
test-embedded-size	38s
	42m 17s

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