Added dotfiles in working directory

Official Documentation:
https://mercurial.selenic.com/wiki/FileFormats#Files_in_the_working_directory
https://mercurial.selenic.com/wiki/Subrepository
The specification for the .hg/ folder is simplified, see:
https://stackoverflow.com/a/15057742

Global/Mercurial.gitignore

-/.hg/*
-*/.hg/*
+.hg/
 .hgignore
+.hgsigs
+.hgsub
+.hgsubstate
+.hgtags