Spring Security HttpSecurityDsl should support apply method

Expected Behavior

``` @Bean fun authSecurityFilterChain(http: HttpSecurity): SecurityFilterChain { http { csrf { disable() } cors { disable() } apply(LoginFilterSecurityConfigurer()) { jwtLogin {

            }
        }
    }
    return http.build()
}

**Current Behavior**

 ```
@Bean
    fun authSecurityFilterChain(http: HttpSecurity): SecurityFilterChain {
        http {
            csrf {
                disable()
            }
            cors {
                disable()
            }
            http.apply(LoginFilterSecurityConfigurer()).jwtLogin {
            }
        }
        return http.build()
    }

The apply keyword will conflict with Kotlin fun

public inline fun <T> T.apply(block: T.() -> Unit): T {
    contract {
        callsInPlace(block, InvocationKind.EXACTLY_ONCE)
    }
    block()
    return this
}

Comment From: sjohnr

@hanrw thanks for the suggestion!

The apply keyword will conflict with Kotlin fun

I'm not 100% sure but it seems like it will take different method parameters so it shouldn't conflict, right?

I think this would be a nice addition, so we don't need to mix a Java and Kotlin approach when using the DSL. Would you like to submit a PR?

Comment From: rishiraj88

Is 'apply' onsidered a keyword here?

Comment From: hanrw

@hanrw thanks for the suggestion!

The apply keyword will conflict with Kotlin fun

I'm not 100% sure but it seems like it will take different method parameters so it shouldn't conflict, right?

I think this would be a nice addition, so we don't need to mix a Java and Kotlin approach when using the DSL. Would you like to submit a PR? The solution could be add apply function in HttpSecurityDsl

    fun <C : SecurityConfigurerAdapter<DefaultSecurityFilterChain, HttpSecurity>> apply(configurer: C): C {
        return this.http.apply(configurer)
    }

Any suggestion?

Comment From: sjohnr

Hi @hanrw!

Any suggestion?

I think that looks like a good start. Just a heads up that if you do submit a PR, we may take a pause on merging it as most new enhancements that will make it into the next release are already scheduled.

Is 'apply' onsidered a keyword here?

I don't believe so, @rishiraj88. I tried something like what @hanrw provided above and it compiles fine as far as I can tell. It would just be an overloaded version of the apply method since it takes different parameters.