Add a "lagoon add task ..." command

[tnelson-doghouse]

Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
I want to create custom tasks more easily

Describe the solution you'd like
Add a "lagoon add task ..." command.

Describe alternatives you've considered
Doing it via GraphQL, which I'm not currently set up for