Core/LootMgr: improved logs of missing *_loot_templates
Core/Players: Fix players not being notified if on loading screen

Fix packets not being sent to players on loading screen even if the system supports these packets to be queued and sent till the player is in world.
There might be additional cases where this applies, please report back if you find any.

Fixes #11339
Core/Player: Additional fixes related to https://github.com/TrinityCore/TrinityCore/commit/ee5eaab598e445e3926edf6e12b1b2b4477c2594

Fix whispers to players on loading screen and few other cases.
Merge pull request #13313 from ShinDarth/335_fix

Improve logs of missing *_loot_templates
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into ghbb