DDF-769, DDF-785 Fixed http proxy, added imagery configuration to standard ui

- fixed issue with http proxy not allowing more than a single
- fixed issue with http proxy returning 404 for all requests
- added configuration for all imagery and terrain providers
- updated ui to access new imagery/terrain configuration
- fixed properties.js to accept new parameters without needing them hardcoded in the ui
DDF-859 - ConfigurationStore now tracks the correct name for imageryProviders and terrainProvider
DDF-864 - cherry picked commits and fixed blueprint issues
DDF-859 - simplified setting the proxiedProvider strings