add action-summary-output option

[szczys]

add functionality to control when a card is added to the Github action summary page.
Valid options:

action-summary-output	behavior
all	results shown in both stderr and action status.
none	results shown only in stderr.
quiet-on-success	matrix success only shown only in stderr, all other output follows same behavior as 'all'.

In all cases, the output of alls-green is still written to stderr. The special case quiet-on-success, any alls-green job in which all matrix steps pass will not publish a card to the action summary but in all other cases (non-success of matrix) the card will still be published.

Resolves #35

[webknjaz]

There's conflicting changes of higher priority that I haven't fished/pushed yet. I'll have to get back to that first, meaning you should expect having to rebase interactively at some point.

But meanwhile, could you document the use case? It sounds like you might be integrating the action incorrectly.

[szczys]

There's conflicting changes of higher priority that I haven't fished/pushed yet. I'll have to get back to that first, meaning you should expect having to rebase interactively at some point.

But meanwhile, could you document the use case? It sounds like you might be integrating the action incorrectly.

I'm happy to rebase as necessary. I've replied to #35 with my use-case. Please let me know if you'd prefer to continue the discussion on this PR instead.