elm 0.19 transition

[gbtb]

It has two major parts:

• Ensure no breaking changes in json libs/syntax happend (maybe it will require addition of an elm-version config field/arg)
• Transfer whole project into 0.19. Major block here is elm-ast, which relies on custom parser lib, which heaily uses custom bin ops, which will be deprecated in 0.19 :D.

[gbtb]

Breaking changes: 0.18-0.19:

1. No more decode in json-decode-pipeline. I can just move to succeed from vanilla package, and not break 0.18 back compat.
2. list, array signature changes, addition of set and dict functions

[gbtb]

Things to consider, if i got to parser change for 0.19:

1. Application should take list of arguments instead of recursion hell