Fix chrome 69 + some theme data related to chats

• Cleaned up Chats theme data in pleromafe.js (slots definitions), had quite a lot of problems by itself
• Added workaround to sort() to make it stable on older browsers (i.e. Array.sort(_ => 0) not returning array with same ordering as before)

screenshot from Chrome 69 running in win10 VM on virtualbox

fixes #890 (closed)

patch is live on sgsgb