Preparation to make decoder use less memory and API more type safe.
Now each scalar type has it's own struct type so it can store different
things and enables to have a scalar interface.
Also own types will enable experimenting with decode DLS designs like
using chained methods that are type aware.
Rename s/interface{}/any/g
Preparation for using generics in decode API and native jq funcations etc
Remove some unused linter ignores as linter has been fixed
