Add hydra OpenAPI description (#750)

* Add swagger config

* Add hydra api info to the README

* hydra.yaml: added some more descriptions

* Add /login

* Add 404/403 responses

* hydra.yaml -> hydra-api.yaml

* Address PR comments

- drop releases/releasename
- document dependency
- document defaultpath

* Fix syntax

* Add project creation

Add `PUT /project/{id}`

* Add /search

* Add "/api/jobsets" endpoint

* Add /api/push endpoint

* Add jobset PUT definition

* Add eval endpoint

* Remove duplicated key

* Fix typo

* Fix structural errors

* fix another error

* Link to hydra-api.yaml from master

* Add openapi yaml validation step to CI

.github/workflows/test.yml

@@ -12,3 +12,11 @@ jobs:
     - uses: cachix/install-nix-action@v8
     #- run: nix flake check
     - run: nix-build -A checks.x86_64-linux.build
+  validate-openapi:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - uses: cachix/install-nix-action@v8
+    - run: nix-shell -p openapi-generator-cli --run "openapi-generator-cli validate -i ./hydra-api.yaml"