Feat/add swagger

[nguyenhoangthuan99]

Fix #1322

Add swagger for api. After running server, go to http://127.0.0.1:3928/swagger to access swagger page.

[dan-menlo]

For easier discoverability, it possible to put this at the root URL (localhost:3928) vs the /swagger route?

[nguyenhoangthuan99]

yes, we can also access to swagger page through http://localhost:3928/swagger

[gabrielle-ong]

@nguyenhoangthuan99

1. I think Daniel is suggesting to use the root url http://127.0.0.1:3928 (or maybe /api?), as a user I may not know to go to /swagger
2. Previous version of cortex.js CLI - cortex start outputed this link, so as a user I can easily click and open the link. Can we bring that back?

Currently:

> cortex start
Host: 127.0.0.1 Port: 3928
Server started

[nguyenhoangthuan99]

I fixed in this pr #1392