doc: Basic documentation of dbus-json1

Closes #1027
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
agent: Add "batch" argument to the 'text-stream' payload

This allows you to specify a size in bytes that we should wait
before we send the data to the front-end.

Fixes #1015
Closes #1016
shell: Put cockpit-about.js in a private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Put cockpit-accounts.js in a private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-cpu-status.js into private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-disk-io-status.js into private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-language.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-i18n.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-jobs.js into cockpit-storage.js

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move journal code into private javascript scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-memory-status.js into private js scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-pages.js into cockpit-main.js private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-login.js into cockpit-main.js private scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-realms.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-server.js into own private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-setup.js into own private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-shutdown.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-system-information.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-terminal.js into private JS scope

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
shell: Move cockpit-util.js into private scope

Remove some unused functions, and move some functions only used in
one place to that other scope.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>