Extensions performance & memory optimisations

Reworked remove_surrounded_chars() to use regular expression ( https://regexr.com/7alb5 ) instead of repeated string concatenations for elevenlab_tts, silero_tts, sd_api_pictures. This should be both faster and more robust in handling asterisks.

Reduced the memory footprint of send_pictures and sd_api_pictures by scaling the images in the chat to 300 pixels max-side wise. (The user already has the original in case of the sent picture and there's an option to save the SD generation).
This should fix history growing annoyingly large with multiple pictures present

extensions/elevenlabs_tts/script.py

@@ -4,6 +4,8 @@ import gradio as gr
 from elevenlabslib import ElevenLabsUser
 from elevenlabslib.helpers import save_bytes_to_path
 
+import re
+
 import modules.shared as shared
 
 params = {
@@ -52,14 +54,10 @@ def refresh_voices():
         return
 
 def remove_surrounded_chars(string):
-    new_string = ""
-    in_star = False
-    for char in string:
-        if char == '*':
-            in_star = not in_star
-        elif not in_star:
-            new_string += char
-    return new_string
+    # regexp is way faster than repeated string concatenation!
+    # this expression matches to 'as few symbols as possible (0 upwards) between any asterisks' OR
+    # 'as few symbols as possible (0 upwards) between an asterisk and the end of the string'
+    return re.sub('\*[^\*]*?(\*|$)','',string)
 
 def input_modifier(string):
     """