Add RouterOperationCustomizer

[hyeonisism]

Summary
The RouterOperationCustomizer customizes the RouterOperation before the path is created so that it is reflected in the document.

Result
As a result, we can change the properties of router operation to give the user a point to customize the document before creating a path.

[junoyoon]

@bnasslahsen

This PR is to prevent overwriting multiple router operations having same path.
RouterOperationCustomizer is introduced for developers to customize routerOperation object properties such as Path.

See below to how to define the RouterOperationCustomizer.
(This impl differentiates the each path by add params into path string if params exist)

https://github.com/springdoc/springdoc-openapi/pull/1706/files#diff-12f0ec82aa8f79cddb6f1649257873491e8c2daab92ba30d35b1b430954dacb3R19-R257

Please review this if you don't mind.

[junoyoon]

@bnasslahsen could you share your valueable time for review and comment for this, please?

[bnasslahsen]

@hyeonisism,

I will add it to my next todo list.

[junoyoon]

@bnasslahsen any progress?

[bnasslahsen]

@bnasslahsen any progress?

merged!

[junoyoon]

Thx @bnasslahsen