add spring security DSL

[pull-vert]

• Complete work of @jonasbark and @skivol, now using DSLs from spring-security 5.4
• Add spring-security support for Spring MVC

fixes #16

For webFlux

webFlux {
    port = 0
    router {
        GET("/public-view") { ok().build() }
        GET("/view") { ok().build() }
    }

    security {
        authenticationManager = repoAuthenticationManager

        http {
            authorizeExchange {
                authorize("/public-view", permitAll)
                authorize("/view", hasRole("USER"))
            }
            httpBasic {}
        }
    }
}

For webMvc

webMvc {
    port = 0
    router {
        GET("/public-view") { ok().build() }
        GET("/view") { ok().build() }
    }

    security {
        authenticationManager = repoAuthenticationManager

        http {
            authorizeRequests {
                authorize("/public-view", permitAll)
                authorize("/view", hasRole("USER"))
            }
            httpBasic {}
        }
    }
}