server: move service factory from hgweb

hgweb: extract app factory I'll move createservice() to the server module, but createapp() seems good to remain in the hgweb module because of its dependency on hgweb/hgwebdir_mod.

server: move service table and factory from commandserver This is necessary to solve future dependency cycle between commandserver.py and chgserver.py. 'cmd' prefix is added to table and function names to avoid conflicts with hgweb.

server: move cmdutil.service() to new module (API) And call it runservice() because I'll soon add createservice(). The main reason I'm going to introduce the 'server' module is to solve future dependency cycle between chgserver.py and commandserver.py. The 'server' module sits at the same layer as the cmdutil. I believe it's generally good to get rid of things from the big cmdutil module.

debugcommands: move 'debugcomplete' in the new module

debugcommands: move 'debugcommands' in the new module The commit message isn't an illusion. There is a "debugcommands" module and command.

debugcommands: move 'debugcheckstate' in the new module

debugcommands: move debug{create,apply}streambundleclone to the new module

debugcommands: move 'debugbundle' in the new module

py3: add os.getcwdb() to have bytes path Following the behaviour of Python 3, os.getcwd() return unicodes. We need bytes version as path variables are bytes in UNIX. Python 3 has os.getcwdb() which returns current working directory in bytes. Like rest of the things there in pycompat, like osname, ossep, we need to rewrite every instance of os.getcwd to pycompat.getcwd to make them work correctly on Python 3.