feat(host-rpc): add RpcAliasOracle with shared positive-result cache #599

Job	Run time
rust-library-base / Feature Checks	2m 24s
rust-library-base / Base Checks / Rustfmt	24s
rust-library-base / Base Checks / Docs	1m 37s
rust-library-base / Base Checks / Clippy	1m 11s
rust-library-base / Base Checks / doctest	2m 19s
rust-library-base / Base Checks / Test Suite	2m 57s
	10m 52s

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