Before this change there was some ambiguity about whether passwords
were obscured on not passing them into config create or config update.
This change adds the --obscure and --no-obscure flags to make the
intent clear.
It also updates the remote control and the tests.
Fixes#3728
Before this change when using "rclone config create" it wasn't
possible to add passwords in one go, it was necessary to call "rclone
config password" to add the passwords afterwards as "rclone config
create" didn't obscure passwords.
After this change "rclone config create" and "rclone config update"
will obscure passwords as necessary as will the corresponding API
calls config/create and config/update.
This makes "rclone config password" and its API config/password
obsolete, however they will be left for backwards compatibility.
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.
