This adds a validation to VSParserHelper to ensure that a field or
script or both are specified by the user. This is technically
required today already, but throws an exception much deeper
in the agg framework and has a very unintuitive error for the user
(as well as eating more resources instead of failing early)
This commit adds back "id" as the key within a script to specify a
stored script (which with file scripts now gone is no longer ambiguous).
It also adds "source" as a replacement for "code". This is in an attempt
to normalize how scripts are specified across both put stored scripts and script usages, including search template requests. This also deprecates the old inline/stored keys.
This change unifies the way scripts and templates are specified for all instances in the codebase. It builds on the Script class added previously and adds request building and parsing support as well as the ability to transfer script objects between nodes. It also adds a Template class which aims to provide the same functionality for template APIs
Closes#11091
Zachary Tong
James Rodewig
Tanguy Leroux
Ryan Ernst
Robert Muir
Dongjoon Hyun
Colin Goodheart-Smithe
Zachary Tong