User some colour variables

client/src/styles/partials/bdsettings/e2ee.scss

@@ -132,7 +132,7 @@
 .bd-encryptedImage::before {
     content: "Encrypted Image";
     position: absolute;
-    background: #3ec99a;
+    background: $colbdgreen;
     width: 100%;
     height: 100%;
     border-radius: 3px;
@@ -158,10 +158,10 @@
     z-index: 1;
     display: block;
     background-size: cover;
-    background-color: #3ecb9c;
+    background-color: $colbdgreen;
     background-repeat: no-repeat;
     border-radius: 100%;
-    border: 2px solid #3ecb9c;
+    border: 2px solid $colbdgreen;
     top: 5px;
     left: 5px;
     opacity: .5;