Add Dynamic ESDL support

Adds changes required for LN feature (Dynamic ESDL).
Refactors ESDL tool to ESDL-xml

Code reviews were performed withing these 4.2.0 pull requests:
https://github.com/hpcc-systems/HPCC-Platform/pull/4482
https://github.com/hpcc-systems/HPCC-Platform/pull/4483