Support global env parameters

[bryanl]

Adds env globals.

ks param set department engineering --env default

creates

COMPONENT INDEX PARAM      VALUE
========= ===== =====      =====
unit      0     data       {"key1":"value1","key2":"value2"}
unit      0     department "engineering"
unit      0     name       "unit"
unit2     0     data       {"key1":"value1","key2":"value2"}
unit2     0     department "engineering"
unit2     0     name       "unit2"

Then you can update the department: ks param set department engineering-advanced --env default

COMPONENT INDEX PARAM      VALUE
========= ===== =====      =====
unit      0     data       {"key1":"value1","key2":"value2"}
unit      0     department "engineering-advanced"
unit      0     name       "unit"
unit2     0     data       {"key1":"value1","key2":"value2"}
unit2     0     department "engineering-advanced"
unit2     0     name       "unit2"

And finally you can remove environment globals: ks param delete department --env=default

COMPONENT INDEX PARAM VALUE
========= ===== ===== =====
unit      0     data  {"key1":"value1","key2":"value2"}
unit      0     name  "unit"
unit2     0     data  {"key1":"value1","key2":"value2"}
unit2     0     name  "unit2"

Fixes #420