Send Team-removal and Sidekick-removal messages

[broxen]

aka: Logging off while on Team, or leaving a Team while Sidekicked asserts false

Summary

Logging off while on Team, or leaving a Team while Sidekicked is hard coded to assert(false) because we have no method of accessing other mapserver's entity lists. We need to develop a Team-Removal event, and Sidekick Removal event to be sent to entities when these methods fire in DataHelpers.cpp

DataHelpers.cpp: removeSidekick()

    assert(false);
    //TODO: this function should actually post messages related to de-sidekicking to our target entity.
    Entity      *tgt            = nullptr; //getEntityByDBID(src_sk.m_db_id);

DataHelpers.cpp: removeTeamMember()

    assert(false);
    // TODO: this should post an Team-removal event to the target entity, since we can't access other server's
    // Entity lists
    Entity *tgt = nullptr; //getEntityByDBID(idx);

Note:

I'd like to get this in before v0.6.0 as it creates an unfriendly user-experience that may result in support-requests from less technical users

[broxen]

I'd like to get this in before v0.6.0 as it creates an unfriendly user-experience that may result in support-requests from less technical users