WYSIWYG Editor automatically cleans up CSS styles

Steps to reproduce:

1. Create a new page (P1) with the following content:

   (% id="00" %)
   ======test1======
   (% align="right" %)test2
   (% align="center" %)test3
   (% style="border: 1pt solid; vertical-align: middle; background-color: rgb(209, 209, 208);" %)test4
   ----
   test5

2. Edit P1 using CK Editor
3. Save P1 -> the content changes to
   • CK Editor:

     ====== test1 ======
     
     (% style="text-align:right" %)test2(%%)
     (% style="text-align:center" %)test3(%%)
     (% style="background-color:#d1d1d0; border:1pt solid; vertical-align:middle" %)test4
     
     ----
     
     test5

   • GWT:

     ====== test1 ======
     
     (% style="text-align:right" %)test2
     (% style="text-align:center" %)test3
     (% style="border: 1pt solid; vertical-align: middle; background-color: rgb(209, 209, 208);" %)test4
     
     ----
     
     test5

You can notice how the line "(% id="00" %)" was deleted, empty lines were added and the content was modified without any input from the user.