Adds new message system for the dashboard
Removes test code
Subheader for the new message system
Don't show the messages in custom installations. Fixed specs
Adds information about the new message system
Don't reopen the already closed notification
Fixes specs
Merge branch 'develop' into feature/CDB-35

* develop: (93 commits)
  Fix success imports not being reported
  Fixed Metrics
  Add upgraded_at to user decorator
  Fix
  Sync upgraded_at attribute on superadmin user's controller, fix specs
  Add upgraded_at attribute to User model
  CDB-148 #resolve [importer] Normalize CSVs with a single column
  [importer] Fix broken spec for Ogr2ogr
  clean up
  [importer] Refactor loader dispatch
  [importer] Implement Loader#supported?
  [importer] Implement OsmLoader#supported?
  [importer] Implement ShpLoader#supported?
  Lower max asset file to 5Mb
  [importer] Refactor calls to CSV normalizers
  [importer] Implement CsvNormalizer.supported?
  [importer] Implement Xslx2Csv.supported?
  [importer] Implement Json2Csv.supported?
  removing loader when there is an error getting column values in color wizard
  Fix vulnerable url download with wget
  ...
Removed old unused code
Adds trial_ends_at to user model
Return trial_ends_at only for magellan accounts
indentation fixed in visualizations-index
CDB-136 #resolved - support block in dashboard is back again
common submodule updated
[importer] Provide a default encoding if none identified
added accepted file type to assets manager uploader
[importer] Provide a default encoding if none identified
[importer] Workaround for eager content-disposition regex
CDB-245 #resolve - fixed problem when drop an unsupported file type
update accepted formats in create new table dialog