Author's Notes: Add per-character author's note

Adds the option to override the chat's author's note with one set
for each character. This saves the pain of having to copy and paste
author's notes for every chat.

Signed-off-by: kingbri <bdashore3@proton.me>

public/scripts/extensions.js

@@ -50,6 +50,7 @@ const extension_settings = {
     memory: {},
     note: {
         default: '',
+        chara: [],
     },
     caption: {},
     expressions: {},