FOGL-2783: Extend directory paths from where Foglamp picks plugins (#1570)
FOGL-2783: Extend directory paths from where Foglamp picks plugins (#1570)

* FOGL-2783: Support for searching plugins in directories mentioned in FOGLAMP_PLUGIN_PATH environment variable

* Further changes

* Code cleanup

* Code cleanup

* Removing debug logs

* Added code to find installed notification rule & delivery plugins from paths given in FOGLAMP_PLUGIN_PATH env var

* Increasing path string length from 128 to MAXPATHLEN

foglamp/FogLAMP,foglamp/FogLAMP,foglamp/FogLAMP,foglamp/FogLAMP