Arvados

• Add a description attribute to the pipeline_instances and jobs models. (See Hacking API server)
• Make an "editable name and description" partial so any object that has a description and name attributes automatically has the same editable name/description section at the top of the page as the current "show project" page.
• Currently the instance#show page shows a misleading description taken from the pipeline template (see #3765). This will be less misleading if we:
  1. Do not show the template's description at all on the instance page.
  2. Do not show the template's name in the same location/style we usually use for properties of the current object. (Perhaps a <div class="alert alert-info"> in the top right corner would be better?)
  3. Add a phrase after the template name/link saying "(note: template has been modified since this instance was created)" when that's true

Also set an initial description field when creating a pipeline instance -- something like

Created using "{template name}" pipeline template on {date/time}

Ideally, arv-run-pipeline-instance should also set the description to something similar. (And accept a command line argument to override)

Note: #3036 adds a description attribute to PipelineInstance and Job (and a name attribute to Job). If #3036 isn't merged when you get started on this, take the 20140815171049_add_name_description_columns.rb migration from the 3036-collection-uuids branch instead of making a conflicting one.