Rename non-Framework project modules

Prior to this commit, the Spring Framework build would mix proper
framework modules (spring-* modules published to maven central) and
internal modules such as:
* "spring-framework-bom" (which publishes the Framework BOM with all
modules)
* "spring-core-coroutines" which is an internal modules for Kotlin
compilation only

This commit renames these modules so that they don't start with
"spring-*"; we're also moving the "kotlin-coroutines" module under
"spring-core", since it's merged in the resulting JAR.

See gh-23282

spring-core/spring-core.gradle

@@ -70,12 +70,12 @@ dependencies {
 	cglib("cglib:cglib:${cglibVersion}@jar")
 	objenesis("org.objenesis:objenesis:${objenesisVersion}@jar")
 	jarjar("org.pantsbuild:jarjar:1.7.2")
-	coroutines(project(":spring-core-coroutines"))
+	coroutines(project(":kotlin-coroutines"))
 
 	compile(files(cglibRepackJar))
 	compile(files(objenesisRepackJar))
 	compile(project(":spring-jcl"))
-	compileOnly(project(":spring-core-coroutines"))
+	compileOnly(project(":kotlin-coroutines"))
 	optional("net.sf.jopt-simple:jopt-simple:5.0.4")
 	optional("org.aspectj:aspectjweaver:${aspectjVersion}")
 	optional("org.jetbrains.kotlin:kotlin-reflect")
@@ -94,7 +94,7 @@ dependencies {
 	testCompile("com.fasterxml.woodstox:woodstox-core:5.2.0") {
 		exclude group: "stax", module: "stax-api"
 	}
-	testCompile(project(":spring-core-coroutines"))
+	testCompile(project(":kotlin-coroutines"))
 }
 
 jar {