Add minimal JiraJob code

[kkaarreell]

This PR adds minimal code for JiraJob class and associated classes Issue and Recipe.

[kkaarreell]

$ REQUESTS_CA_BUNDLE=/etc/pki/tls/cert.pem newa event jira
produces few jira- files like this one

$ cat jira-128049-RHEL-8.10.0-NEWA-12.yaml
erratum:
  builds: []
  release: RHEL-8.10.0
event:
  id: '128049'
  type_: erratum
jira:
  id: NEWA-12
recipe:
  url: https://path/to/recipe.yaml

The new keys here are jira and recipe. This file is currently created only when job_recipe is defined in the configuration.