Use saml 1.1 and ws-security libraries to build metadata and messages

[tvdijen]

• Relies on Prefix filenames with file:// if necessary, or openssl will fail xml-security#54 to be merged.
• Relies on Disconnect ADFS-module from SimpleSAMLphp simplesamlphp#2227 to be merged (reason for failing tests)

[codecov]

Codecov Report

Attention: Patch coverage is 1.47601% with 267 lines in your changes missing coverage. Please review.

Project coverage is 3.25%. Comparing base (b12a0ad) to head (0be6586).
Report is 52 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##             master     #22      +/-   ##
===========================================
- Coverage      3.92%   3.25%   -0.67%     
- Complexity       73     103      +30     
===========================================
  Files             5       3       -2     
  Lines           408     492      +84     
===========================================
  Hits             16      16              
- Misses          392     476      +84