add first bits of jinja template support

bot/templates/boot.msg

@@ -0,0 +1,14 @@
+```
+________                          __
+\_____  \ _____  _____    _______/  |_
+ /   |   \\__  \ \__  \  /  ___/\   __\
+/    |    \/ __ \_/ __ \_\___ \  |  |
+\_______  (____  (____  /____  > |__|
+        \/     \/     \/     \/
+
+{{bot_name}} {{version}}
+git hash: {{git_hash}}
+debug_mode: {{debug}}
+```
+
+https://github.com/LAION-AI/Open-Assistant

bot/templates/rate_summary.msg

@@ -0,0 +1,7 @@
+Rate the following summary:
+{{task.summary}}
+
+Full text:
+{{task.full_text}}
+
+Rating scale: {{task.scale.min}} - {{task.scale.max}}

bot/templates/welcome.msg

@@ -0,0 +1,6 @@
+Hi there,
+
+I am the **Open-Assistant Junior Bot** 🤖. I would love to get your feedback 🤗!
+Currently I am still learning from human demonstrations how to reply to instructions. When I am grown up I want to become a fully functional AI Assistant language model that is fully open-sourced and assists millions of humans all over the world.
+
+Type `/tutorial` to start the tutorial or `/help` to see a list of all my commands.