fix: apply theme on the fly in preferences, theme-store refactoring

Signed-off-by: Roman <ixrock@gmail.com>

src/renderer/themes/kontena-dark.json

@@ -1,6 +1,7 @@
 {
-  "name": "Lens Dark Theme",
+  "name": "Dark (Lens)",
   "type": "dark",
+  "description": "Original Lens dark theme",
   "author": "Lakend Labs",
   "colors": {
     "blue": "#3d90ce",

src/renderer/themes/kontena-light.json

@@ -1,6 +1,7 @@
 {
-  "name": "Lens Light Theme",
+  "name": "Light (Lens)",
   "type": "light",
+  "description": "Original Lens light theme",
   "author": "Lakend Labs",
   "colors": {
     "blue": "#3d90ce",