Connect build to ge.spring.io

This change publishes a build scan to ge.spring.io for every local
build from an authenticated Spring committer and for CI where
appropriate access tokens are available. The build will not fail if
publishing fails.

This change also allows the build to benefit from remote build caching,
providing faster builds for all contributors.

Additionally, the project will have access to all features of Gradle
Enterprise such as:

- Dashboards to view all historical build scans, along with performance
   trends over time
- Build failure analytics for enhanced investigation and diagnosis of
   build failures
- Test failure analytics to better understand trends and causes around
   slow, failing, and flaky tests

README.md

@@ -1,3 +1,5 @@
+[![Revved up by Gradle Enterprise](https://img.shields.io/badge/Revved%20up%20by-Gradle%20Enterprise-06A0CE?logo=Gradle&labelColor=02303A)](https://ge.spring.io/scans?search.rootProjectNames=webflow)
+
 # Overview
 
 Spring Web Flow facilitates building web applications that require guided navigation -- 

gradle.properties

@@ -1 +1,2 @@
 version=3.0.1-SNAPSHOT
+org.gradle.caching=true

settings.gradle

@@ -5,6 +5,11 @@ pluginManagement {
 	}
 }
 
+plugins {
+	id 'com.gradle.enterprise' version '3.14.1'
+	id 'io.spring.ge.conventions' version '0.0.14'
+}
+
 rootProject.name = 'webflow'
 
 include 'spring-binding'