[Feature/Improvements] Delete data sources from metadata db when using app.delete()

[deshraj]

Description

Changes:

• Delete row from data sources whenever someone calls app.delete()
• Delete the chat history when someone calls app.reset()
• Add support for passing custome bm25encoder when using pinecone vector database

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Unit Test

[codecov]

Codecov Report

Attention: Patch coverage is 35.71429% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 56.44%. Comparing base (92dd7ed) to head (10ed893).

Files	Patch %	Lines
embedchain/embedchain.py	33.33%	8 Missing ⚠️
embedchain/vectordb/pinecone.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1286      +/-   ##
==========================================
- Coverage   56.49%   56.44%   -0.06%     
==========================================
  Files         151      151              
  Lines        6101     6110       +9     
==========================================
+ Hits         3447     3449       +2     
- Misses       2654     2661       +7     

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