debugcommands: use temporary dict for its command table Instead, load the table by commands.py so the debug commands should always be populated. The table in debugcommands.py is unnamed so extension authors wouldn't be confused to wrap debugcommands.table in place of commands.table.

commands: move debugcommands and debugcomplete back to commands module These commands depend heavily on the commands table, so it doesn't make much sense to isolate them to debugcommands.py. This helps eliminating the future import cycle.

commands: move templates of common command options to cmdutil (API) The goal is to get rid of the debugcommands -> commands dependency. Since globalopts is the property of the commands, it's kept in the commands module.