Feat/new UI (#13)

* new custom theme

* improve css: scrollbar, header, tabs and buttons

* update settings tab

* open file index selector by default

* update chat control panel

* update chat panel

* update file index page

* cap gradio<=4.22.0

* rename admin page

* adjust UI

* update flowsettings

* auto start in browser

* change colour for edit LLM page's button

libs/kotaemon/pyproject.toml

@@ -22,7 +22,7 @@ dependencies = [
     "theflow",
     "llama-index>=0.9.0,<0.10.0",
     "llama-hub",
-    "gradio>=4.0.0",
+    "gradio>=4.0.0,<=4.22.0",
     "openpyxl",
     "cookiecutter",
     "click",