feat: add app shell (angular-material)

Add app shell built using angular-material and flex-layout. Refractor
code due to configuration changes.

Fixes #52

src/main.scss

@@ -4,7 +4,71 @@
  */
 
 // Theme customization
+@import "~@angular/material/prebuilt-themes/indigo-pink.css";
 
 // 3rd party libraries
 
 // Other imports
+
+/* You can add global styles to this file, and also import other style files */
+body, html {
+  width: 100%;
+  height: 100%;
+  position: relative;
+  overflow: hidden;
+  -webkit-tap-highlight-color: transparent;
+  min-height: 100%;
+  -webkit-font-smoothing: antialiased;
+}
+
+html {
+  font-size: 16px;
+}
+
+body {
+  margin: 0;
+  padding: 0;
+  font-weight: 400;
+  font-size: .875rem;
+  color: rgba(0,0,0,.87);
+  line-height: 1.5;
+  font-family: Roboto, Helvetica Neue, sans-serif;
+}
+
+div {
+  box-sizing: border-box;
+}
+
+.mat-icon-button.xs-button {
+  height: 20px;
+  width: 20px;
+  line-height: 20px;
+}
+
+.mat-icon-button.xs-button .mat-icon {
+  font-size: 16px;
+  line-height: 20px;
+  height: 20px;
+  width: 20px;
+}
+
+.text-muted {
+  color: rgba(0, 0, 0, .54);
+}
+
+.mb-05 {
+  margin-bottom: .5rem;
+}
+
+.mr-05 {
+  margin-right: .5rem;
+}
+
+.mb-1 {
+  margin-bottom: 1rem;
+}
+
+.mt-1 {
+  margin-top: 1rem;
+}
+