C6 Rename characters SQL table obj_Id field to charId

[Mobius]

Rename characters SQL table obj_Id field to charId.
The main reason to do this, is achive compatibility with other branches that are based on l2jserver.
https://pastebin.com/uqig6fjH

Note: The subscriber version already uses this.

[Mobius]

Reminder: characters primary key must change as well.

PRIMARY KEY  (charId),