added data format to metadata internally

[aaishikdutta]

Description

Added data type to the metadata object.

Fixes #258

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested by logging metadatas_with_metadata variable before pushing to db for a Youtube video:

from embedchain import App

app = App()
app.add("youtube_video", "https://youtu.be/ilIefxbSJT8")

This adds 'embedchain_data_type': 'youtube_video' to the metadata object for each document

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

Maintainer Checklist

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Made sure Checks passed

[taranjeet]

should we call it data_type?

[aaishikdutta]

updated