feat(rest): allow basePath in RestServer configuration

[kjdelisle]

Part of #914

Add the capability to set basePath as a part of your config.

Checklist

• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• Related API Documentation was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in packages/example-* were updated

[kjdelisle]

Keep in mind that this requires more unit tests, which I'll add later.
EDIT: This also does not include the functional changes that make use of the configuration, yet.

[raymondfeng]

I don't see any code to use server-level basePath? Is it to be implemented?

[kjdelisle]

It will be a part of a subsequent commit in this PR, but it'll need to wait until @jannyHou lands #916

[jannyHou]

hi @kjdelisle there is some change for the basePath in PR #916 , I believe it's highly twisted with the problem you are addressing. I just realized the controllerSpec also has a basePah, thought it is the same as openapiSpec level one but it's not.

Could you hold on adding more code and we do a pair programming next week? Thanks :)

[bajtos]

IMO, this is not needed for our MVP, therefore this pull request should be closed until MVP is done. If we consider non-configurable basePath as a problem, then let's fix the docs please.

[kjdelisle]

This PR can probably be closed, since the final form of what we're working with will change based on @jannyHou 's upcoming update to move us to OpenAPI v3.

[jannyHou]

@kjdelisle I had a talk with @bajtos this morning, most of the basePath in rest server component refers to controller level basePath, not app level basePath, so I am not going to address this feature(configured app level basePath) in the v2-->v3 PR.

And please note in the coming openapi3 spec, there is no root level property called basePath, it is merged into servers[{url: '<a_url>'}]