COMPASS-4263: limit docs for out preview

[alenakhineika]

Description

When importing agg pipeline form text limit documents used for a preview even if pipeline includes the out stage, otherwise the aggregation will be executed on the whole collection and freeze the UI. Even tho according to the design the out stage should be the last stage in the pipeline and we expect that all documents should be exported to another collection, we can still use the limit stage here because we don't start exporting yet. To do so a user should click the Save Documents button, and only then the pipeline without limiting will be executed.

For more details see: https://github.com/mongodb-js/compass-aggregations/pull/268
Ticket: https://jira.mongodb.org/browse/COMPASS-4263

I also fixed lint warnings and GitHub templates, since I have noticed these small issues and it was a quick win.

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[Anemy]