Changes on sd webui api stuff

- Strip url of trailing slashes, this caused issues when your api url
  ended with a slash (such as the default! at least i think)
- Notify the user if they didn't call sd webui with the --api argument,
  which is required to use the api
- Don't try to write to non-existant art directory, just send b64 image
  like the diffusers function does it. In the future we probably want to
  save these, but it would be in standardized manner most likely tied to
  story files somehow

aiserver.py

@@ -9381,33 +9381,33 @@ def text2img_api(prompt,
         "negative_prompt": "{}".format(koboldai_vars.img_gen_negative_prompt),
         "sampler_index": "Euler a"
     }
-    apiaddress = '{}/sdapi/v1/txt2img'.format(koboldai_vars.img_gen_api_url)
+    apiaddress = '{}/sdapi/v1/txt2img'.format(koboldai_vars.img_gen_api_url.rstrip("/"))
     payload_json = json.dumps(final_imgen_params)
     logger.debug(final_imgen_params)
-    #print("payload_json contains " + payload_json)
-    submit_req = requests.post(url=f'{apiaddress}', data=payload_json).json()
-    if submit_req:
-        results = submit_req
-        for i in results['images']:
-            final_src_img = Image.open(BytesIO(base64.b64decode(i.split(",",1)[0])))
-            buffer = BytesIO()
-            final_src_img.save(buffer, format="Webp", quality=95)
-            b64img = base64.b64encode(buffer.getvalue()).decode("utf8")
-            base64_bytes = b64img.encode('utf-8')
-            img_bytes = base64.b64decode(base64_bytes)
-            img = Image.open(BytesIO(img_bytes))
-            dt_string = datetime.datetime.now().strftime("%H%M%S%d%m%Y")
-            final_filename = "stories/art/{}_{}".format(dt_string,filename)
-            pnginfo = PngImagePlugin.PngInfo()
-            prompttext = results.get('info').split("\",")[0].split("\"")[3]
-            pnginfo.add_text("parameters","prompttext")
-            img.save(final_filename, pnginfo=pnginfo)
-            logger.debug("Saved Image")
-            koboldai_vars.generating_image = False
-            return(b64img)
-    else:
+    submit_req = requests.post(url=apiaddress, data=payload_json)
+
+    if submit_req.status_code == 404:
+        show_error_notification(
+            "SD Web API Failure",
+            f"The SD Web UI was not called with --api. Unable to connect.",
+            do_log=True
+        )
+        return None
+    elif not submit_req.ok:
+        show_error_notification("SD Web API Failure", f"HTTP Code {submit_req.status_code} -- See console for details")
+        logger.error(f"SD Web API Failure: HTTP Code {submit_req.status_code}, Body:\n{submit_req.text}")
         koboldai_vars.generating_image = False
-        logger.error(submit_req.text)
+        return None
+
+    results = submit_req.json()
+
+    try:
+        base64_image = results["images"][0]
+    except (IndexError, KeyError):
+        show_error_notification("SD Web API Failure", "SD Web API returned no images", do_log=True)
+        return None
+
+    return base64_image
 
 #@logger.catch
 def get_items_locations_from_text(text):