Improved cloudflare storage types

[swalker326]

The cloudflare storage adapter would throw an error when passing the KVNamespace type that is generated from running wrangler types

Set the cloudflare storage adapter to accept a generic type so I can pass the generated KvNamespace type from the generated worker-configuration.d.ts which is the result from running wrangler types

return issuer({
      storage: CloudflareStorage<KVNamespace>({
        namespace: env.CloudflareAuthKV,
      }),

The storage adapter still defaults to the types that come from the cloudflare provided worker types.

closes #316