Added NotificationV2 and Group Events to Pipeline Tutorial

[VinyarionHyarmendacil]

The following pipeline events are mostly documented, barring the properties specified:

NotificationV2 Events:

• notification-v2
  • $.content.type: incomplete enum
  • $.content.category: incomplete enum
  • $.content.relatedNotificationsId: not sure what a gpos is
  • $.content.link: unknown scheme values?
  • $.content.responses[].type: incomplete enum
  • $.content.responses[].data: unknown formats depending on type
  • $.content.responses[].icon: incomplete enum
• notification-v2-update
• notification-v2-delete

Group Events:

• group-joined
• group-left
• group-member-updated
  • $.content.member.membershipStatus: incomplete enum
  • $.content.member.visibility: incomplete enum
• group-role-updated

[Rexios80]

I don't know enough about this to comment. If it looks good to @Foorack it's good for me.

[VinyarionHyarmendacil]

129 addressed, forgot to refer earlier