[CORE] include admin key in EVT_CLIENT_KICK data dict when available

This make sure to have the same "pattern" for EVT_CLIENT_BAN, EVT_CLIENT_BAN_TEMP, EVT_CLIENT_KICK. When the admin is not available the key is simply mapped over None
[TESTS] updated tests so they do not fail with the new EVT_CLIENT_KICK event generation
Merge pull request #195 from FenixXx/release-1.10

Added 'admin' key in EVT_CLIENT_KICK data dict