Bug 16699: Split parameters and paths in Swagger

Bug 16699: Split parameters and paths in Swagger

Parameters and paths should be split in our Swagger specification, because
otherwise swagger.json would become messy with all the paths and their
further specification in the same file. Also parameters should be split
for the same reason.

Instead of using index.json for definitions, parameters and paths, we define
new files "definitions.json", "parameters.json" and "paths.json" in order to
simplify the references. If we kept using index.json and try to reference
"/definitions/error.json" from "/paths/holds.json", reference would be
"../definitions/index.json#/error" instead of now simplified version,
"../definitions.json#/error".

Here is the proposed structure:

.
├── swagger.json
├── definitions.json
├── paths.json
├── parameters.json
├── definitions
│   └── error.json
│   └── patron.json
├── parameters
│   └── patron.json
├── paths
│   └── patrons.json
├── minifySwagger.pl
└── swagger.min.js

The swagger.json paths, definitions and parameters will look as follows:
...
  "paths": {
    "$ref": "paths.json"
  },
  "definitions": {
    "$ref": "definitions.json"
  },
  "parameters": {
    "$ref": "parameters.json"
  }
...

A problem with splitting specification into multiple files directly from
swagger.json (e.g. "paths": { "$ref": "paths.json" }) is that it is not
following the Swagger specification and an error will be thrown by the
Swagger-UI default validator (online.swagger.io/validator).

To overcome this problem, we use the minifySwagger.pl script from Buug 16212.
This allows the developers to work with the structure introduced in this patch
thus allowing developers to split the specification nicely, and still have a
valid Swagger specification in the minified swagger.min.json.

To test:
-2: Apply the minifier-patch in Buug 16212.
-1: Make sure you can validate your specification with Swagger2 validator at
    online.swagger.io/validator/debug?url=url_to_swaggerjson, or install it
    locally from https://github.com/swagger-api/validator-badge.

1. Don't apply this patch yet, but first validate swagger.json
   with swagger.io-validator (or your local version, if you installed it)
2. Observe that validation errors are given
3. Run minifySwagger.pl
4. Validate swagger.min.json with the validator you used in step 1
5. Observe that validation passes and we overcame the invalid specification
   problem in swagger.min.json
6. Apply this patch
7. Run minifySwagger.pl
8. Repeat step 4
9. Observe that validation passes with new structure
10. Run REST tests at t/db_dependents/api/v1

(11. Study the new structure of our Swagger specifications :))

Signed-off-by: Olli-Antti Kivilahti <olli-antti.kivilahti@jns.fi>
My name is Olli-Antti Kivilahti and I approve this commit.
We have been using the Swagger2.0-driven REST API on Mojolicious for 1 year now
in production and I am certain we have a pretty good idea on how to work with
the limitations of Swagger2.0
We participated in the development of the Mojolicious::Plugin::Swagger and know
it well. We have made an extension to the plugin to provide full CORS support
and have been building all our in-house features on the new REST API.

Signed-off-by: Johanna Raisa <johanna.raisa@gmail.com>
My name is Johanna Räisä and I approve this commit.
We have been using Swagger2.0-driven REST API in production successfully.

Signed-off-by: Benjamin Rokseth <benjamin.rokseth@kul.oslo.kommune.no>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>