INT-3422: Add `ChannelInterceptorAware.remove()`

JIRA: https://jira.spring.io/browse/INT-3422

* Add two methods:
```
boolean removeInterceptor(ChannelInterceptor interceptor);
boolean removeInterceptor(int index);
```

The method `removeInterceptorsOfType(Class<?> clazz)` isn't good, because we lead undesired behavior, when several provided interceptors might be of the same type (e.g. by superclass)

Anyway I'm open for discussion. E.g. how about `clean()` ?
OK. Why don't follow with `Collection` contract here? Remove by index - object; remove object - boolean.