[FLINK-19095] [remote] Add "expireMode" to YAML function state spec

With this new key in YAML modules, users can now specify expire mode
independently for each state. Note that for remote functions, the
expiration mode "after read and write" is semantically equivalent to
"after each function invocation". Therefore, the modes supported are
"after-invoke" and "after-write" for remote functions to keep semantics
clear.
2 files changed