Upgrade to Boot 3.x

- For now port spring-native to framework config.
- 3rd party configs should go somewhere else.
- Fix changes from javax to jakarta.
- Change java settings as we now require jdk 17.
- Fixes #385

spring-shell-docs/src/test/java/org/springframework/shell/docs/CommandContextSnippets.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.shell.docs;
 
-import javax.validation.constraints.Null;
+import jakarta.validation.constraints.Null;
 
 import org.springframework.shell.command.CommandContext;