[ticket/12860] Add template events mcp_ban_fields

PHPBB3-12860
[ticket/12860] Add template events mcp_ban_unban

PHPBB3-12860
[ticket/12860] Fix typo

PHPBB3-12860
Merge pull request #2747 from Elsensee/ticket/12860

[ticket/12860] Add template events to mcp_ban.html

* Elsensee/ticket/12860:
  [ticket/12860] Fix typo
  [ticket/12860] Add template events mcp_ban_unban
  [ticket/12860] Add template events mcp_ban_fields