Modernize typescript package

TS SDK is currently generated by tsc, which doesn't generate standard module syntax. This is the index.js:

'use strict';
var __createBinding =
	(this && this.__createBinding) ||
	(Object.create
		? function (o, m, k, k2) {
				if (k2 === undefined) k2 = k;
				var desc = Object.getOwnPropertyDescriptor(m, k);
				if (
					!desc ||
					('get' in desc ? !m.__esModule : desc.writable || desc.configurable)
				) {
					desc = {
						enumerable: true,
						get: function () {
							return m[k];
						},
					};
				}
				Object.defineProperty(o, k2, desc);
			}
		: function (o, m, k, k2) {
				if (k2 === undefined) k2 = k;
				o[k2] = m[k];
			});
var __exportStar =
	(this && this.__exportStar) ||
	function (m, exports) {
		for (var p in m)
			if (p !== 'default' && !Object.prototype.hasOwnProperty.call(exports, p))
				__createBinding(exports, m, p);
	};
Object.defineProperty(exports, '__esModule', { value: true });
__exportStar(require('./spacetimedb'), exports);
__exportStar(require('./identity'), exports);
__exportStar(require('./address'), exports);
__exportStar(require('./client_db'), exports);
__exportStar(require('./message_types'), exports);

This isn't standard compliant and more importantly, redundant.

Solution:

Use rollup-based setup to bundle this. We can use https://github.com/egoist/tsup, which uses rollup for bundling(everything in one single JS file rather than multiple), generates d.ts, and sourcemaps all in one go with minimal config. I use it for all my npm packages and can't recommend it enough.

Start with the TS SDK package setup and the generated index.js shown in the issue, then review how tsc currently produces the package. Evaluate a tsup or rollup-based build for bundled JavaScript, declarations, and sourcemaps; done means the package emits standard module syntax and the existing SDK exports remain available.