BE 1.5 - Implement filter_general API function

[notjackl3]

Create an API function to filter volunteers by their general information (such as email, phone, position, etc.). Here are some resources:

• Our Supabase dashboard's documentation on how to work with Volunteers table
• Our Supabase Volunteer table schema.

Params:

• < op>: string - Either "AND" [to require matching all values] or "OR" [to require matching any of the values])
• < column>: string - a single column to filter for (e.g. name_org, email, position, etc.)
• < values>: List< string> - the values from the same column to filter for (e.g. f2f, front_desk)

Returns:

• the resulting rows after filtering

Notes:

• Make sure to include all of the personal information that a user may have:
   - name_org
   - pseudonym
   - pronouns
   - email
   - phone
   - position
   - opt_in_communication
• The API functions should be written inside src/lib/api/
• Ensure proper error handling and validation of input data
• If you need to install any dependency, write about it on your PR.

The goal is to:

• Create a GET endpoint that accepts a single general information filter parameters and returns filtered volunteer data from Supabase
• Return appropriate success/error responses with HTTP status codes.