feat(android app): add 'choose file' button to auto upload media to catbox in the background

more free and open web hosting services can be added later

src/components/post-form/post-form.module.css

@@ -125,13 +125,13 @@
   .postFormTable td input {
     height: 20px;
   }
-
+  
   .postFormTable td textarea {
     height: 80px;
   }
 
   .postFormTable button {
-    padding: 4px 8px;
+    padding: 3px 6px;
   }
 }
 
@@ -139,4 +139,14 @@
   .postFormMobile {
     display: none;
   }
+}
+
+.uploadButton button {
+  position: relative;
+  margin: 0;
+  margin-right: 5px;
+}
+
+.uploadButton span {
+  font-weight: normal;
 }