Add levels to resources and enable filtering based on the resource level

[dsebastien]

Resources should have a level:

• Beginner

• Intermediate

• Advanced

• Expert

• [ ] Add level to resources

• [ ] Let users filter resources by level

[dsebastien]

Update the supabase-db-seed.sql script.

• Truncate contents: https://www.tutorialspoint.com/postgresql/postgresql_truncate_table.htm#:~:text=The%20PostgreSQL%20TRUNCATE%20TABLE%20command,wish%20to%20store%20some%20data.
• Add the entries

Truncate so that we can easily reset the db locally