FE for group level Cycle Analytics - refactor old feature into Vue

What does this MR do?

This is a followup MR from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14891 and will need to be rebased against master once the originating MR has been merged.

The aim of this is to refactor the old cycle analytics code (which was reused in the above mentioned MR) from HAML / Vue into Vue.

The changes for this allow for the old and new code to co-exist by making use of a cookie flag on the frontend.

Top level feature flag

analytics

Cookie flag

document.cookie = "cycle_analytics_app=true"

Issue

https://gitlab.com/gitlab-org/gitlab-ee/issues/12753

Follow up issue to remove cookie flag

https://gitlab.com/gitlab-org/gitlab-ee/issues/13569

Context

https://gitlab.com/gitlab-org/gitlab-ee/issues/12753#note_200647766

Screenshots

Stage selected	No access to stage data	No data available

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content

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Requirements

• Copy code which can be reused to analytics namespace
  • Existing components which were rendered from HAML
  • Store
  • Service
  • SVGs
• Create new components
  • Base component
  • Summary table
  • Stage table
• Migrate to Vuex store
• Ensure there's sufficient test coverage
  • Feature specs
  • Stage components
  • Vuex store