feat: add server-side pagination, sort and search to groups component (#507)

- Add server-side pagination, sort and search to groups component
- Refactor code to conform to current guidelines

See: #234

src/app/groups/groups.component.scss

@@ -1,27 +1,10 @@
+.container {
+  .action-button{
+    margin-left: auto;
+  }
 
-  table {
-    width: 100%;
+  .search-button{
+    min-width: 30px;
+    margin: 4px;
   }
-  
-  .mat-form-field {
-    font-size: 14px;
-    width: 100%;
-  }
-  
-  td, th {
-    width: 15%;
-  }
-  
-  .filter{
-    width: 50%;
-  }
-  
-  .inactive {
-    color: red;
-  }
-  
-  .active {
-    color: green;
-  }
-  
-  
+}