support for custom, top-level configuration entries about enterprise-components

[pawelhudak]

usage example:

custom.qsd content:

[group]
  cfg.x = <type(INT), default(100)>

system.cfg content:

[...]
commonLibs = custom
cfg.x = 200

[group:core]
  cfg.x = 300

  [[core.tick]]
    cfg.x = 400
    [...]

  [[core.rdb]]
    [...]

[group:tmp]
  [[tmp.rdb]]
    [...]

retreival of cfg.x on core.tick process:

.cr.getCfgField[`THIS;`group;`cfg.x]   // =  400

retreival of cfg.x on core.rdb process:

.cr.getCfgField[`THIS;`group;`cfg.x]   // = 300

retreival of cfg.x on tmp.rdb process:

.cr.getCfgField[`THIS;`group;`cfg.x]   // = 200