Fixes #37: initial implementation of security integration (automatic login using georchestra security headers)

[mbarto]

• upgraded MapStore to latest master
• backend: custom geostore security configuration to automatically login using georchestra security proxy headers
  • username taken from header sec-username
  • groups taken from header sec-roles
  • role ADMIN assigned if user has group MAPSTORE_ADMIN
• frontend automatic login at page load
• (temporary) plugin to show current user role
• (temporary) admin page skeleton

To test locally I suggest using the "Modify Headers" chrome extension to automatically set headers. This is an example:

[landryb]

Just my 2c - it seems the PR mixes various things in a single commit, ie upgrading mapstore bits (isnt it supposed to just be 'point the submodule at another commit' ?) + adding some local config (pointing at hardcoded georchestra.geo-solutions.it urls ?) and adding the bits to configure the header auth module in geostore-spring-security.xml, and maaany other seemingly unrelated bits.

For the sake of clarity & history readability, can we get meaningful commits with clearly identified changes ? Or its just a first shot and not meant for final review/merge ?