[ADD] cli: db manager

Currently dbs can only be managed via the UI in order to take
filestores in account: while it's possible to load/copy/rename/drop
databases via `psql`, that will not manage the related filestores so
the result of the operation is incomplete DBs and leftover filestores
littering the disk.

Seems like a good idea to add a CLI to perform the same
tasks. Currently the CLI calls into the corresponding service, rather
than both calling into (possibly better designed) unified APIs, but
that seems fine for an initial version.

The top-level `db` command acts as a db manager, with git-style
sub-sub-commands for the various operations:

- `load` to load a dump file into a database (with a specified name or
  not)
- `dump` to dump a local db to a zip dump (pg_dump can be created via
  the corresponding command so not a concern)
- `duplicate` and `rename`
- `drop` in order to drop both the database itself and the
  corresponding filestore

Notably, `create` is currently left out because a database can
trivially be created by invoking odoo using a dbname which doesn't
exist, so doesn't seem useful.

`list` is also left out, because `psql -l` generally does the job.

closes odoo/odoo#97365

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

odoo/cli/command.py

@@ -8,16 +8,11 @@ import odoo
 from odoo.modules import get_modules, get_module_path, initialize_sys_path
 
 commands = {}
-
-class CommandType(type):
-    def __init__(cls, name, bases, attrs):
-        super(CommandType, cls).__init__(name, bases, attrs)
-        name = getattr(cls, name, cls.__name__.lower())
-        cls.name = name
-        if name != 'command':
-            commands[name] = cls
-
-Command = CommandType('Command', (object,), {'run': lambda self, args: None})
+class Command:
+    name = None
+    def __init_subclass__(cls):
+        cls.name = cls.name or cls.__name__.lower()
+        commands[cls.name] = cls
 
 class Help(Command):
     """Display the list of available commands"""