[FIX] core: missing doc for some subcommands

Run `odoo-bin help`, you'll notice that some descriptions are missing,
this commit fixes that.

Run `odoo-bin shell --help`, you'll notice that the `usage:` line says
`odoo-bin [options]` instead of `odoo-bin shell [options]`. Other
commands that depend on the server cli are broken too. Fix those too.

closes odoo/odoo#120285

Signed-off-by: Vincent Schippefilt (vsc) <vsc@odoo.com>