Backend: Allow pass object to inputs

Problem

Users want to be able to use object as inputs for include templates. Currently supported array, string, boolean. https://docs.gitlab.com/ci/yaml/#specinputstype

Example usage is to pass CI CD variables to specific job in template

Proposal

Allow for the use of object inputs in a CI Header definition:

spec:
  inputs:
    some_object: 
      type: object
      default:
        EXAMPLE: 'value'
        EXAMPLE2: 'postgres'