Simplify bash completion for service options
Simplify bash completion for service options

Previously, the completions for `--xxx` and the corresponding
`-xxx-add` and `-xxx-rm` options were defined in separate blocks.
This caused a lot of duplicated code.

This PR removes duplication for xxx=config|group|host|placement-pref|secret.

Now the blocks for `create` and `update` only contain completions for
options that either only exist for the particular command or are specific
to it (completions for `--env-rm` and `--env|env-add` differ).

Signed-off-by: Harald Albers <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@albersweb.de>

thaJeztah/cli,dnephin/cli,docker/cli,dnephin/cli,cpuguy83/cli,docker/cli,thaJeztah/cli,cpuguy83/cli