Add a new javascript API for submitting an RRD that is stored directly as bytes

[jleibs]

What

• This was motivated by Release updated Gradio Support #2013

This API means that an RRD file transmitted over a side-channel such as gradio can be injected directly into the viewer instead of needing to point the viewer at a separate url.

Tested with an adhoc svelte component:

<script lang="ts">
    import { WebViewer, LogChannel } from "@rerun-io/web-viewer";

    import { onMount } from "svelte";

    let rr: WebViewer;
    let ref: HTMLDivElement;
    let channel: LogChannel;

    onMount(() => {
        rr = new WebViewer();
        rr.start(undefined, ref).then(() => {
            channel = rr.open_channel("gradio");
        });

        return () => {
            channel.close();
            rr.stop();
        };
    });

    let data1 = '...'
    let data2 = '...'
    let data3 = '...'

    function push(data: string) {
        var intermediate = atob(data);
        var buff = new Uint8Array(intermediate.length);
        for (var i = 0; i < intermediate.length; i++) {
            {
                buff[i] = intermediate.charCodeAt(i);
            }
        }
        channel.send_rrd(buff);
    }

</script>

<div class="container">
    <button on:click={() => push(data1)}>
    Data1
    </button>
    <button on:click={() => push(data2)}>
    Data2
    </button>
    <button on:click={() => push(data3)}>
    Data3
    </button>
</div>

<div class="viewer" bind:this={ref} />

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

To run all checks from main, comment on the PR with @rerun-bot full-check.

[nikolausWest]

Reminder to update any relevant js package docs + our Rerun on web docs on the main docs site as part of this stream of (very awesome) work