Create string_consts.h and pull string consts from player.cpp and character.cpp

[Ramza13]

Summary

SUMMARY: Infrastructure "Create string_consts.h and pull string consts from player.cpp and character.cpp"

Purpose of change

Having the various string consts copied all over the place is really annoying and potentially error prone. This is the start of creating a single file to contain organize and possibly eventually comment on them.

Describe the solution

Created file string_consts.h, then removed all string consts from player.cpp and character.cpp and combined and alphabetically sorted them.

Describe alternatives you've considered

Testing

Additional context

[jbytheway]

If these are in a header then they should probably no longer be marked static. I suspect clang-tidy would have complained about that, but it didn't get a chance to run in this PR's Travis run.