AMALIB: Add base things for the cache on client-side

src/rust/Cargo.lock

src/rust/Cargo.toml

src/rust/amalib/Cargo.toml

src/rust/amalib/src/cache.rs

src/rust/amalib/src/db_objects.rs

src/rust/amalib/src/lib.rs

src/rust/amalib/src/tags.rs