AppKernel: modify xdmod source for php7 compatibility

[jsperhac]

Description

Fixed up xdmod core source based on the output of php7cc version compatibility checker (https://github.com/sstalle/php7cc). This provided an opportunity to delete some woefully dated source code that used deprecated syntax and packages.

Refer to pull requests against ubccr/xdmod#101 and https://github.com/ubccr/xdmod-xsede/pull/29 repos for associated changes for php7 compatibility.

As spelled out in the original commit remarks:

• Renamed an AppKernel namespace class from Resource to AKResource

Motivation and Context

This PR helps prepare xdmod for a migration to a newer PHP version, and provides the opportunity to prune some unused and outdated code.

Tests performed

All existing integration and unit tests were run without incident. Where coverage is limited (e.g. user profile), manual testing was done to (hopefully) ensure no behavioral changes were introduced.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project as found in the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.