docs: Add tags to all json specs

[johnchaffee]

A tag has been added to each endpoint that matches the last path of the endpoint. This allows common APIs to be grouped by tag in Swagger UI.

For example, the following 5 endpoints are all grouped under the "Messages" tag:

POST    /2010-04-01/Accounts/{AccountSid}/Messages.json
GET     /2010-04-01/Accounts/{AccountSid}/Messages.json
DELETE  /2010-04-01/Accounts/{AccountSid}/Messages/{Sid}.json
GET     /2010-04-01/Accounts/{AccountSid}/Messages/{Sid}.json
POST    /2010-04-01/Accounts/{AccountSid}/Messages/{Sid}.json

You can view the spec + tags rendered in Swagger UI here:

https://johnchaffee.github.io/twilio-swagger/api/api_v2010/

Fixes #74

I added these tags using this script, which you are welcome to clone.

[childish-sambino]

This issue has been added to our internal backlog to be prioritized as it changes generated configuration. +1s on the issue summary will help it move up the backlog (DI-2364).

[Tim-Heartbeat]

Any chance for this to get merged in or anywhere where I can upvote that issue as having the ability to more selectively import models would be nice