CORE-5200 Fixed executions/list endpoint filtering.

Reimplemented the 'filter' param for the executions/list endpoint, adapted from the original metadactyl endpoint (metadactyl-clj@7e555095dd2ba18a62b121835179093e7823288d).
Refactored the documentation for this endpoint to use a markdown formatted table, so that embedded markdown will also be rendered.
Added case-insensitive searching of UUIDs for the 'id' filter parameter.