[ticket/12928] core.mcp_reports_gather_query_before

Adding the core.mcp_reports_gather_query_before
event to mcp backend.

PHPBB3-12928
[ticket/12928] Update to RC4

PHPBB3-12928
Merge pull request #2826 from brunoais/ticket/12928

[ticket/12928] core.mcp_reports_gather_query_before