Add simple app functionality

This commit enables anyone to create a app and add 3 types of data
sources:

* pdf file
* youtube video
* website

It exposes a function called query which first gets similar docs from
vector db and then passes it to LLM to get the final answer.

embedchain/utils.py

@@ -0,0 +1,10 @@
+import re
+
+
+def clean_string(text):
+    text = text.replace('\n', ' ')
+    cleaned_text = re.sub(r'\s+', ' ', text.strip())
+    cleaned_text = cleaned_text.replace('\\', '')
+    cleaned_text = cleaned_text.replace('#', ' ')
+    cleaned_text = re.sub(r'([^\w\s])\1*', r'\1', cleaned_text)
+    return cleaned_text