EngineBlock 4.4.0

Security & Push Metadata release.

Fixes minor security issues found (no known exploits) and introduces support for multiple sources of metadata.
Supported out of the box are:

• OpenConext Stoker
• Janus REST API v1
• Local database. Particulairly useful when filled with Janus Push metadata.

Metadata Repositories can be composed and ordered.

Notable issues resolved with this release:

• Push service configuration to EngineBlock #67
• Open Redirect vulnerabilities in Profile #113
• XSS in HTTP Host header #111
• Make it also possible (and configurable) to use ePPN for the identifier instead of SHO+uid #98
• Disable the loading of external entities in XML documents.