completion: add bluetoothctl zsh completions

completion: add bluetoothctl zsh completions

This zsh compdef provides completions for the bluetoothctl command.

It has been modified from version 1 of this patch to get the command
names and descriptions from the newly introduced --zsh-complete.

It utilizes the output of `bluetoothctl devices` or
`bluetoothctl controllers` to provide a descriptive completion menu
in those contexts.

e.g.

$ bluetoothctl connect <TAB>
04:52:C7:0C:D4:A7  -- Bose QuietComfort 35
40:4E:36:D9:8F:28  -- Pixel 2
A4:38:CC:20:5D:E0  -- Pro Controller

Change-Id: Ib06fa64d1cf86b6bc6439d6f99ef36d042ed3ec1
Signed-off-by: himanshu <h.himanshu@samsung.com>