Swagger docs for the REST API (#141)

* Add (incomplete) swagger docs for the REST API

* Add information about execution result

* Minor tweaks

* Remove unused type

* Group models

* List required fields

* Vanilla code generation

* Add the config which generates default models (documenting behavior)

* Move swagger file closer to the source of all truth

* Add a makefile

* Split server, client and models

* Explicit type names (no anonymous structs)

* Changing the approach again because of some codegen corner cases

* Pretty well rounded scheme

* Update code references

* Remove petstore URL

* Switch to using new server code

api/Makefile

@@ -0,0 +1,14 @@
+
+
+all: server client models
+
+
+server:
+	oapi-codegen --config ./server.yaml ./b7s-swagger.yaml
+
+client:
+	oapi-codegen --config ./client.yaml ./b7s-swagger.yaml
+
+models:
+	oapi-codegen --config ./models.yaml ./b7s-swagger.yaml
+