requestMappingMode: Explicit configuration to control the location of the generated class level RequestMapping annotation

Since #10573, the @ RequestMapping has been moved from the controller to the generated api interface.
This introduced incompatibilities in many scenarios, but specially when spring-cloud is used as a library. Unfortunately the fix from @MelleD (#13546) does not allow to override the default (for example when using interfaceOnly). This PR introduces a dedicated cli option to decide where the RequestMapping annotation should be placed.

`
requestMappingMode
Where to generate the class level @RequestMapping annotation. (Default: controller)
iface - Generate the @RequestMapping annotation on the generated Api Interface.
controller - Generate the @RequestMapping annotation on the generated Api Controller Implementation.
none - Do not add a class level @RequestMapping annotation.

`

The default is controller, which is the same as before #10573. By explicitly using iface, the annotation could be added to the api interface.

Caused By

• [Spring] Fix generated api ignore basePath #10573

Based on

• Remove wrong request mapping for feign clients #13546

Fixes

• [BUG] Java/Spring: @RequestMapping is unconditionally added to controller with property expression #13552
• [BUG] @RequestMapping annotation not allowed on @FeignClient interfaces #13488

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