Move pipeline routes under ee src tree

[knolleary]

Description

Moves the pipeline specific routes into the EE src tree.

Routes affected:

• GET /api/v1/application/:id/pipelines - get pipelines in an application
• POST /api/v1/application/:id/pipelines - create a new pipeline
• DELETE /api/v1/application/:id/pipelines/:pipelineId - delete a pipeline
• POST /api/v1/pipelines/:pipelineId/stages - create new pipeline stage
• GET /api/v1/pipelines/:pipelineId/stages/:stageId - get pipeline stage details

Adds the following set of permissions for these routes:

'pipeline:view': { description: 'View a pipeline', role: Roles.Member },
'pipeline:edit': { description: 'Edit a pipeline', role: Roles.Owner },
'application:pipelines:create': { description: 'Create a pipeline within an application', role: Roles.Owner },
'application:pipelines:list': { description: 'List pipelines within an application', role: Roles.Member },
'application:pipelines:delete': { description: 'Delete a pipeline from an application', role: Roles.Owner }

Related Issue(s)

#2075

[Pezmc]

I'm going to approve and merge this into 2075-application-pipelines, so I can do further work in that branch before the wider team is awake.