docs: updating readme and display version for rebranding (#2550)

* docs: updating readme and display version for rebranding

- CELLxGENE -> CELLxGENE Annotate
- reverting __init__.py display_version back to "cellxgene"
- changing page titles to "CELLxGENE | Annotate"

client/index.html

@@ -3,7 +3,7 @@
   <head>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
-    <title>cell&times;gene</title>
+    <title>CELL&times;GENE | Annotate</title>
     <style>
       html,
       body,

client/index_template.html

@@ -3,7 +3,7 @@
   <head>
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
-    <title>cell&times;gene</title>
+    <title>CELL&times;GENE | Annotate</title>
     <style>
       html,
       body,

client/src/components/app.js

@@ -41,7 +41,7 @@ class App extends React.Component {
     const { loading, error, graphRenderCounter } = this.props;
     return (
       <Container>
-        <Helmet title="cellxgene" />
+        <Helmet title="CELL&times;GENE | Annotate" />
         {loading ? (
           <div
             style={{