Request to make where clause optional in queries

[BakedJesus]

🚀 The feature

Currently, if no where clause is provided then it's set to filter using app_id (this is implemented in embedchain.py at _retrieve_from_database). This can get annoying when I am using external libraries for storing the data in chroma. Currently, my workaround is to set where = [{"index" > 0 }] which grabs all the entries from chroma.

Motivation, pitch

Current workaround is computationally wasteful. Please allow no where clause for app._retrieve_from_database