Revert "Revert "bump version to v1.15.0.0dev""

This reverts commit 082483ad6a0d0f7b114c92837dfe7b9a6ae13771.
Revert "Revert "add easyconfig files to EasyBuild v1.13.0 and v1.14.0""

This reverts commit 7373101b23d3ad6e9e0a9b71e9784ada389c8917.