move away from json-schema-to-typescript

Currently we're depending on `json-schema-to-typescript`, however, it's limited (as noted here https://github.com/pyramation/cosmwasm-typescript-gen/issues/10) so we should look into fully parsing/processing types internally

examples to inspire

https://github.com/iamssen/cosmwasm-typescript-generator/blob/main/cosmwasm-typescript-generator/src/transform/createTypeStore.ts

https://github.com/bcherny/json-schema-to-typescript/blob/master/src/typesOfSchema.ts

https://github.com/bcherny/json-schema-to-typescript/blob/master/src/types/JSONSchema.ts