Add email notifications on job completion / failure

[alahiff]

We can use the "email" field in the data returned by the query to the IAM /userinfo endpoint (fortunately email is included in the scope when the OIDC client is registered).

[fcasson]

Email on completion would be really useful for JINTRAC users (probably second highest priority after running snapshots #80)

[alahiff]

The following commits: https://github.com/prominence-eosc/prominence/commit/83241e7707ef4f32e5ef41599d0ab9dee3e6e48e https://github.com/prominence-eosc/prominence/commit/1e2a1c9692c53f971d3921704152f28488eec724 https://github.com/prominence-eosc/prominence/commit/3eb67b0d83f17164920b9241d2a551fceeb2138e https://github.com/prominence-eosc/prominence/commit/7eff9144b985b6ed769fab8ad49f7ce1ff956a03 https://github.com/prominence-eosc/prominence/commit/cce61a95de2f11df1b29aec83e4f29c442707e5d https://github.com/prominence-eosc/prominence/commit/511bdc75c08b1e3ce13013bb4b8bfa94eab3b7ba https://github.com/prominence-eosc/prominence/commit/70b0ca354e28d3a471613a9e2642c4f7a05d86f1 https://github.com/prominence-eosc/prominence/commit/a4f9345e51ba4ae4ca20390017f60eaae64d3ec9 https://github.com/prominence-eosc/prominence/commit/1129f0d4fcccc82a704f32adb490cd3f4c74b08b https://github.com/prominence-eosc/prominence/commit/a885c680c3865e7fa53f4f3489064549937c19c9 enable users to define notifications in a job or workflow. Currently only the following is supported for jobs:

  "notifications": [
    {
      "event": "jobFinished",
      "type": "email"
    }
  ]

Other event types are likely to be supported, and notification types other than email could be added in future. The email address used is taken from the OIDC /userinfo endpoint, i.e. the email address registered in IAM.