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

The issue names no repository files, tests, or entry points. Start by reviewing the current json-schema-to-typescript integration, then compare the referenced createTypeStore.ts, typesOfSchema.ts, and JSONSchema.ts examples. Done should mean the project fully parses and processes types internally without that dependency, but the issue does not define the exact scope or validation criteria.

索引モデルが issue の本文から書いたものです。