[RFE] apply fast schema to fast template yaml files

[DumpySquare]

Like other pieces of the ATC, validating the declaration during the authoring process can be extremely helpful.

Fast has a schema for yaml files. Looking to validate fast yaml templates with that schema to provide insight during the authoring process

I took a quick try to get this working but there seems to be some parsing differences. Will continue researching

Schema: https://github.com/f5devcentral/f5-fast-core/blob/master/schema/template.json

AS3 schema as referece: https://raw.githubusercontent.com/F5Networks/f5-appsvcs-extension/master/schema/latest/as3-schema.json

A schema validator: https://jsonschemalint.com/#!/version/draft-07/markup/json

Could also use this to add in a FAST snippet