Support named log groups

Describe the enhancement

Currently, it is possible to wrap logs in collapsible groups through ::group:: and ::endgroup::. The former accepts an optional string, which is used as the title of the collapsible header. However, the endgroup does not support any additional argument. As a result, it is not possible to uniquely identify the matching start and end statements, thus, preventing nesting, hierarchical view, etc.

The implementation of this feature in other services allows using a keyword to match open and close statements.

Code Snippet

echo "::group::Title"
echo "Foo"
echo "::endgroup::"

Possible enhancement:

echo "::group::mykey::Title"
echo "Foo"
echo "::endgroup::mykey::"

Additional information

Since composite actions can include other actions (up to 10 levels of hierarchy), log groups are likely to conflict. Keywords might be implicitly used for enhancing the current UI.

Refs: #802 #1272 #1279 #1404

/cc @thboop @andreineculau @pbartolome

Start by tracing the existing handling of the ::group:: and ::endgroup:: workflow commands in the runner and reviewing the related issues #802, #1272, #1279, and #1404. The work is complete when named opening and closing statements are consistently recognized, including the proposed syntax and the nesting or hierarchy behavior described in the issue.