Core/Logs: Added more info for .send mail command.
Core/Command: Rework PInfo and give more output and add Gender to trinity_string

* Prints out in several strings instead of few
* Leaves unnecessary ones out (e.g. phase for GMs)
* Some code documentation included (including doxygen)
* Cleaner code (partly)
* Prints more content, e.g.:
** Localized Class- and Race names
** Localizable Gender names
** Current experience, required experience
** And more

Shoutouts to @Nay, @Subv, @Shauren and several others from the irc

Core/Command: Rework PInfo and give more output and add Gender to trinity_string
support 1.12.3 (build 6141)
Core: Fix warnings
Core/Command: Remove excess parameter in LANG_PINFO_PLAYER

Should fix the command on linux servers
Implement .arena commands