Separate configuration from pdp/__init__.py

[jameshiebert]

Portal config options should be separated out from pdp/__init__.py such that:

• all portal pages should be moved into portal/*.py files
• nothing is actually executed in __init__.py
  • e.g. the test suite should be able to import symbols from pdp and select what it executes (based on what marks/fixtures are selected at run time)
• the most commonly used config options are factored out to a yaml config file
  • app_root
  • geoserver_url
  • ncwms_url
  • auth_required (True|False) (this may become moot, eventually)
  • jsmin (True|False)
  • pcds_dsn
  • mm_dsn

[basilveerman]

Fixed with c07b87f61136a35120d352b95f7147248b9d169f