Add a new section to Tenancy docs about non-Filament tenancy

[PovilasKorop]

I described it in my own words but I guess @danharrin you would write it a bit differently, feel free to make any edits/restructuring.

• [ X ] Changes have been thoroughly tested to not break existing functionality.
• [ X ] New functionality has been documented or existing documentation has been updated to reflect changes.
• Visual changes are explained in the PR description using a screenshot/recording of before and after.

[what-the-diff]

PR Summary

• Simplified Multi-tenancy in Eloquent
  The team has introduced a segment focussing on the aspect of 'multi-tenancy' (ability of a software to work for multiple users at the same time) in Eloquent in a comprehensible manner. They've also provided a practical example displaying the use of Eloquent Observers and Global Scopes, which are tools within the Eloquent framework that help filter data. In this case, the data is filtered by a team_id field in the Post model, allowing the software to handle multiple teams' data separately and securely.

• Correction of Textual Errors
  Additionally, a few minor alterations have been made to improve the readability of the text, and a typo found in the document has also been corrected.

[danharrin]

Thanks!