Add host() method to docket

[cbornet]

This PR enables overriding the default host from the Docket.

• if "host" is not set, then the behavior will be the same as the current one (use the properties file or the swagger def endpoint hostname)
• if "host" is set, then it will be used.

Fixes #764

[cbornet]

@dilipkrish Tell me if you are OK with this. If OK, please wait that I add unit tests before merging.

[dilipkrish]

looks good to me 👍 only I'd say on the docket add an @Incubating annotation with 2.3 as the version

[dilipkrish]

Also it doesn't seem like using @SwaggerDefinition is going to work for this issue

[dilipkrish]

Is this ready for merge? Trying to close it out so I can include in 2.3

[cbornet]

Arf! There is a conflict. I will solve it today.

[cbornet]

Rebase done and unit tests OK --> ready to merge 😄

[dilipkrish]

@cbornet done! thanks for being patient 🤘