GMEJSONNode and Typescript Refactor

[umesh-timalsina]

Based on a conversation with @brollb, we decided that it might be nice to add additional support with typescript for webgme-json-importer json format that adheres to the schema.

[brollb]

It is worth noting that using types should prevent internal bugs (or bugs when calling from typescript) but won't do any runtime checking. For that, we would need something like JSON schema (or using rust and wasm but that is a bigger jump and probably wouldn't be worth the bigger effort).

[brollb]

We could also use something like TypeDoc potentially