Setup website with docusaurus (#11)

Summary:
Set up landing page, docs page, and html versions of the ipython notebook tutorials.
Pull Request resolved: https://github.com/fairinternal/pytorch3d/pull/11

Reviewed By: gkioxari

Differential Revision: D19730380

Pulled By: nikhilaravi

fbshipit-source-id: 5df8d3f2ac2f8dce4d51f5d14fc336508c2fd0ea

website/core/Footer.js

@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ */
+const PropTypes = require("prop-types");
+const React = require('react');
+
+function SocialFooter(props) {
+  const repoUrl = `https://github.com/${props.config.organizationName}/${props.config.projectName}`;
+  return (
+    <div className="footerSection">
+      <div className="social">
+        <a
+          className="github-button" // part of the https://buttons.github.io/buttons.js script in siteConfig.js
+          href={repoUrl}
+          data-count-href={`${repoUrl}/stargazers`}
+          data-show-count="true"
+          data-count-aria-label="# stargazers on GitHub"
+          aria-label="Star PyTorch3d on GitHub"
+        >
+          {props.config.projectName}
+        </a>
+      </div>
+    </div>
+  );
+}
+
+SocialFooter.propTypes = {
+  config: PropTypes.object
+};
+
+class Footer extends React.Component {
+  docUrl(doc, language) {
+    const baseUrl = this.props.config.baseUrl;
+    const docsUrl = this.props.config.docsUrl;
+    const docsPart = `${docsUrl ? `${docsUrl}/` : ''}`;
+    const langPart = `${language ? `${language}/` : ''}`;
+    return `${baseUrl}${docsPart}${langPart}${doc}`;
+  }
+
+  pageUrl(doc, language) {
+    const baseUrl = this.props.config.baseUrl;
+    return baseUrl + (language ? `${language}/` : '') + doc;
+  }
+
+  render() {
+    const repoUrl = `https://github.com/${this.props.config.organizationName}/${this.props.config.projectName}`;
+    return (
+      <footer className="nav-footer" id="footer">
+        <section className="sitemap">
+          <SocialFooter config={this.props.config} />
+        </section>
+
+        <a
+          href="https://opensource.facebook.com/"
+          target="_blank"
+          rel="noreferrer noopener"
+          className="fbOpenSource">
+          <img
+            src={`${this.props.config.baseUrl}img/oss_logo.png`}
+            alt="Facebook Open Source"
+            width="170"
+            height="45"
+          />
+        </a>
+        <section className="copyright">{this.props.config.copyright}</section>
+      </footer>
+    );
+  }
+}
+
+module.exports = Footer;