Reduce number of managed Netty dependencies

Now that reactor-netty has a strict set of transitive dependencies, this
commit refactors the managed dependencies to only list the required
ones. `netty-all` is still managed to avoid conflicts when pulled by
other libraries.

Fixes gh-8553

spring-boot-dependencies/pom.xml

@@ -850,11 +850,6 @@
 				<artifactId>netty-codec-socks</artifactId>
 				<version>${netty.version}</version>
 			</dependency>
-			<dependency>
-				<groupId>io.netty</groupId>
-				<artifactId>netty-codec-stomp</artifactId>
-				<version>${netty.version}</version>
-			</dependency>
 			<dependency>
 				<groupId>io.netty</groupId>
 				<artifactId>netty-common</artifactId>
@@ -872,27 +867,17 @@
 			</dependency>
 			<dependency>
 				<groupId>io.netty</groupId>
-				<artifactId>netty-transport</artifactId>
-				<version>${netty.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>io.netty</groupId>
-				<artifactId>netty-transport-udt</artifactId>
+				<artifactId>netty-resolver</artifactId>
 				<version>${netty.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>io.netty</groupId>
-				<artifactId>netty-transport-sctp</artifactId>
-				<version>${netty.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>io.netty</groupId>
-				<artifactId>netty-transport-rxtx</artifactId>
+				<artifactId>netty-transport</artifactId>
 				<version>${netty.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>io.netty</groupId>
-				<artifactId>netty-resolver-dns</artifactId>
+				<artifactId>netty-transport-native-epoll</artifactId>
 				<version>${netty.version}</version>
 			</dependency>
 			<dependency>