Create a component to handle a collapsible block

Problem to solve

There are multiple places in application where we have a block to collapse/expand on click. Would be nice to abstract this behavior to shared component.

Example:

Collapsed	Expanded

Proposal

Create a Vue shared component to reuse where we need a collapsible block

Links / references

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24724#note_137631500