Grails 7 - Add optional Micronaut Support

[jamesfredley]

update micronaut test projects to use Micronaut Spring Boot starter

https://micronaut-projects.github.io/micronaut-spring/latest/guide/#springBootStarter

https://github.com/micronaut-projects/micronaut-spring/blob/5.8.x/spring-boot-starter/src/main/java/io/micronaut/spring/boot/starter/MicronautImportRegistrar.java

currently commented out in settings.gradle

commit: grails/grails-functional-tests@bfdf2f5

//include 'micronaut' micronaut has been removed from Grails can be restored based on https://micronaut-projects.github.io/micronaut-spring/latest/guide/#springBootStarter

//include 'issue-11767' micronaut has been removed from Grails can be restored based on https://micronaut-projects.github.io/micronaut-spring/latest/guide/#springBootStarter
//include 'issue-11767-plugin'
//project(':issue-11767-plugin').projectDir = new File('plugins/issue-11767-plugin')

[jdaugherty]

micronaut-projects/micronaut-core#11965 blocks this. I've created micronautTests branch as a starting point for this (it's no where near done, but we can't proceed if GSPs are processed by Micronaut and trigger a compile failure).