issue note component rename

What does this MR do?

remove issue_ prefix from simple note components

does not move them into vue_shared folder because I am not convinced that they belong there. It would break the app structure, e.g

vue_shared
  components
    note_edited_text.vue
    note_header.vue
  store
    actions.js
    getters.js   <- these are not shared - ONLY used by notes components

if we instead did vue_shared/notes/(components|store|mixins) then we retain normal app structure while still indicating that this is a shared component.

Are there points in the code the reviewer needs to double check?

if I missed anything

Why was this MR needed?

part of https://gitlab.com/gitlab-org/gitlab-ce/issues/38178

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Review
  • Has been reviewed by Frontend
• Squashed related commits together

What are the relevant issue numbers?

Ticks some boxes on https://gitlab.com/gitlab-org/gitlab-ce/issues/38178