fix(deps): update dependency @material/web to v1

This CL also fixes many things necessary for the update.

It also changes the entire md3 theme, since there have been a lot of
breaking changes and this is the easiest way to have a working theme
again (it is also an improvement).

Change-Id: I4a412e0c0ca4345084c724fcaba000293521e907
diff --git a/src/workflows/manager/index.js b/src/workflows/manager/index.js
index 113177c..b3b08d2 100644
--- a/src/workflows/manager/index.js
+++ b/src/workflows/manager/index.js
@@ -1,4 +1,5 @@
 import '@material/web/fab/fab.js';
+import '@material/web/icon/icon.js';
 import './components/List.js';
 import './components/AddDialog.js';
 import './components/WorkflowDialog.js';
@@ -50,8 +51,8 @@
       <p>Workflows allow you to run a customized list of actions on a thread easily.</p>
       <wf-list .workflows=${this._workflows}></wf-list>
       <md-fab ${ref(this.addFabRef)}
-          icon="add"
           @click=${this._showAddDialog}>
+        <md-icon slot="icon">add</md-icon>
       </md-fab>
       <wf-add-dialog ${ref(this.addDialog)}>
       </wf-add-dialog>