Moved frontend of REST Mock to frontend container (solves #168)

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: #186
Reviewed-by: Mikolaj Widla <widlam@noreply.example.com>

Frontend/assets/css/tools/mock/common.css

@@ -0,0 +1,32 @@
+@import url('https://necolas.github.io/normalize.css/8.0.1/normalize.css');
+/* @import url('https://fonts.googleapis.com/icon?family=Material+Icons'); */
+@import url('r11addons.css');
+@import url('r11tables.css');
+@import url('r11tool.css');
+@import url('r11tooltip.css');
+@import url('r11modal.css');
+@import url('r11flexbox.css');
+
+@font-face {
+    font-family: 'Material Icons';
+    font-style: normal;
+    font-weight: 400;
+    src: url(https://fonts.gstatic.com/s/materialicons/v140/flUhRq6tzZclQEJ-Vdg-IuiaDsNc.woff2) format('woff2');
+}
+  
+.material-icons {
+    font-family: 'Material Icons';
+    font-weight: normal;
+    font-style: normal;
+    font-size: 24px;
+    line-height: 1;
+    letter-spacing: normal;
+    text-transform: none;
+    display: inline-block;
+    white-space: nowrap;
+    word-wrap: normal;
+    direction: ltr;
+    -moz-font-feature-settings: 'liga';
+    -moz-osx-font-smoothing: grayscale;
+}
+