Reorganize types generated for typescript clients

[joshua-spacetime]

NOTE: Cherry-picking #4127 from the 2.0-breaking-changes branch.

Original PR Description

This changes generated types in ts client bindings. We currently generate a few different types of types: reducer args, procedure args, rows, and user defined types. To avoid potential conflicts between these types (for example, if a user defined a type called FooRow, and also had a tabled named foo, we would end up with two types named FooRow), this puts each set of types in a different file and namespace. We also stopped exporting the xxxRow types, because there is always another type generated for those. We now have a types directory, which has an index.ts with user defined types, along with reducers.ts and procedures.ts for the types generated for reducer/procedure parameters.

import type * as Types from './module_bindings/types';

var currentMessages: Types.Message[] = [];

or

import { type Message } from './module_bindings/types';

var currentMessages: Message[] = [];

This has a couple other changes:

• For procedure and reducer types, this adds a suffix of Args, since we may want types for the return values in the future.
• For all of the types, instead of exposing the schema object, we are now giving the typescript type (e.g. export type Message = __Infer<typeof MessageRow>;). I couldn't think of a reason for users to want the schema object, so this should save users from needing to do all of the Infer boilerplate.

This is a breaking change for v2.

2. This only changes typescript, and it should generally make thing easier to use.