yaml os discovery now respects the os mib_dir definition
mib_dir now only allows strings, not arrays
changed schema validation to account for that
consolidated dell mibs, no reason for them to be spread out
* New os Eltek WebPower - files + test files
* OS eltek-webpower - minor fix to mib query.
* OS eltek-webpower - sensor and state data improvements.
* OS Eltek Webpower - Created battery symmetry test and battery bank delta voltage support.
* OS Eltek Webpower - symmetry code fix.
* OS Eltek Webpower - symmetry code fix.
* OS Eltek Webpower - symmetry code fix.
* new os eltek - rectifier state fix
* Updated json test data
* Update eltek-webpower.json
* Update eltek-webpower.yaml
* Update eltek-webpower.yaml