Provide a way to get all stacks from stack ls

[lukehoban]

We recently made a change to improve the performance of stack ls - but as part of that also changed the correctness of stack ls -a to not report all stacks if there are more than 300. A warning is issued when there are more - but it does not indicate what users can do to actually get all stacks.

We should:

1. Provide a way to actually get all stacks
2. Possibly make that the default again for stack ls -a
3. If we do continue to limit by default, include enough information in warning for users to actually get all stacks (or limit query by project If necessary).

Cross ref slack discussion.

Other notes:

I would recommend adding the 300 Max to the documentation so users will not rely on it (as we did) with their automation tools.
if i use a tag filter with the CLI will it still hide results? Cause i still see the warning. Where as if i use the project filter i don't

[jasminen]

@lukehoban Thanks for addressing this issue!

I did some tests and indeed filtering by tag will hide some results even if result set size is < 300 . My guess is that all stacks are returned and then filtered by tag - which hits the Max 300 limit.