Add HashiCorp Nomad provider (#483)

* provider: adding Nomad provider

* updating CONTRIBUTING.md with Nomad provider

* updated README.md by adding the Nomad provider

* fix typo

* adding nomad/api and nomad/testutil deps

* adding Nomad binary dependency for provider tests

* fixed the nomad binary download command step and added tolerations to the nomad provider.

* adding nomad provider demo gif

* adding my name to authors

* adding two missing go-rootcerts files after dep ensure

* delete pod comment

.circleci/config.yml

@@ -35,6 +35,18 @@ jobs:
       - run:
           name: Build
           command: V=1 make build
+      - run:
+          name: Install Nomad
+          command: |
+            curl \
+              --silent \
+              --location \
+              --output nomad.zip \
+              https://releases.hashicorp.com/nomad/0.8.6/nomad_0.8.6_linux_amd64.zip && \
+            unzip nomad.zip && \
+            chmod +x nomad && \
+            mv nomad /go/bin/nomad && \
+            rm nomad.zip
       - run:
           name: Tests
           command: V=1 CI=1 SKIP_AWS_E2E=1 make test