Update ASF "stash" action to allow list of keys

In the new "caching" mechanism we are using "stash" GitHub action from @assignUser which only allows one key per action.

The action is in https://github.com/apache/infrastructure-actions/tree/main/stash

This is a a limiting factor when we want to download artifacts with a dynamic list of keys coming from a variable (say list of keys derived python versions - "3.9 3.10 3.11 3.12" -> "key-3.9 key-3.10 key-3.11 key-3.12".

Currently in https://github.com/apache/airflow/pull/45266 (https://gtithub.com/apache/airflow/pull/45266/files#diff-a2dbc854d7d9f769ffe6efe98247baa68750cba87d785fb70d4616331010c7d0) we are hard-coding the possible actions to run with parameters and we are skipping those that are not on the list, but this is more of a hack than target solution.

Ideally we should be able to pass `keys` parameter to the action instead of `key` and be able to produce "hit-keys" list as output - then we could generate and pass the list of keys as input.

Start by reading the ASF infrastructure-actions stash action at the linked stash path, then compare its current single-key behavior with the usage in apache/airflow#45266. Done means the action accepts a list of keys, supports dynamically generated inputs, and exposes the keys that were found as a hit-keys output.

Written by the indexing model from the issue text.