feat: generate SDK from Swagger

[arjunyel]

Using Deno's dnt build system, the SDK is now a Deno project that generates a cross-platform NPM distribution.

There are breaking changes:

• All the calls are nested in sections now, for example, client.createBillableMetric() becomes client.billableMetrics.createBillableMetric()
• the returns of API calls are Fetch API Responses. If there are no errors the data property will be available

import { Client, getLagoError } from 'lago-javascript-client';

const lagoClient = Client('__YOUR_API_KEY__');

try {
    const { data } = await lagoClient.billableMetrics.createBillableMetric(billableMetric);
} catch (error) {
    const lagoError = await getLagoError<typeof lagoClient.billableMetrics.createBillableMetric>(error);
}

Closes https://github.com/getlago/lago-nodejs-client/issues/47