Proposal: add field to #hiring-job-board offers with contract type

[alexpdp7]

Many offers, esp. remote offers are for "contractor/freelancer/autónomo/self-employed" positions, because foreign companies without a Spanish legal entity cannot offer regular employee contacts.

Personally, I find this non-ideal, because I'm only interested in regular employee positions, and it makes it very hard to spot them.

I would propose a simple field with "employee" and other options.