Replace cache with a third party library

[KwilLuke]

The cache that is implemented in this SDK is too error prone and not worth maintaining.

We should implement either:

• An isomorphic cache library (or a nodejs cache library with the appropriate polyfills, but that is not ideal because it forces polyfills onto the consumers of the SDK) - candidates include node-cache and memory-cache
• Use a nodeJS cache in nodeKwil and use localstorage for webKwil - this may require some more refactoring, but may be the better solution if there is not a good isomorphic cache library.

Or, we can just remove the cache! It only helps make less calls to .getSchema() when building transactions (we call the schema to validate that the required inputs are present). That seems like an overoptimization given the scale at which kwil is currently being used.