Add support for tab completion in the CLI

[timbeiko]

Add support for tab completion wherever possible (for options, flags and subcommands) in the CLI. Default to PicoCLI’s built in behavior when possible.

Acceptance Criteria:
A user sees the options, flags and subcommands available to them when they begin typing and can tab through them to select the appropriate one.

[macfarla]

Teku implemented this so look at what they do

[diega]

@macfarla, are you referring to this PR?

[macfarla]

Yes I think so! Are you interested in working on this one @diega ?

[diega]

yes, I can take this

[macfarla]

Great - assigned to you @diega !