New Feature: Implement @Resource and generate-resource-controller for RxGORM

Trying to create test `rx-mongodb` and create new `domain-resource` on **Grails 3.2.0 RC1**
not able to run basic scenario as described below:
### Task List
- [x] Stacktrace (if present) provided
- [x] Example that reproduces the problem uploaded to Github
- [x] Steps to reproduce provided
- [x] Full description of the issue provided (see below)
### Steps to Reproduce
1. Create New Project
`grails create-app myapp --profile=angular -features=rx-mongodb,json-views,asset-pipeline`
2. Create Domain Resource
`create-domain-resource myapp.Todo`
3. `run-app`
### Expected Behaviour

I should be able to access Todo list when I access `http://localhost:8080/todo`
### Actual Behaviour

Error

```
ERROR org.grails.web.errors.GrailsExceptionResolver - IllegalStateException occurred when processing request: [GET] /todo
No transactionManager was specified. Using @Transactional or @Rollback requires a valid configured transaction manager. If you are running in a unit test ensure the test has been properly configured and that you run the test suite not an individual test method.. Stacktrace follows:
java.lang.reflect.InvocationTargetException: null
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: No transactionManager was specified. Using @Transactional or @Rollback requires a valid configured transaction manager. If you are running in a unit test ensure the test has been properly configured and that you run the test suite not an individual test method.
at grails.transaction.GrailsTransactionTemplate.(GrailsTransactionTemplate.groovy:60)
... 3 common frames omitted
```
### Environment Information
- **Operating System**: MacOS
- **Grails Version:** 3.2.0 RC1
- **JDK Version:** 1.8
- **Container Version (If Applicable):** N/A
### Example Application

``` groovy
package myapp

import grails.gorm.rx.mongodb.*
import org.bson.types.ObjectId

import grails.rest.*

@Resource(uri="/todo", readOnly=false, formats = ["json", "xml"] )
class Todo implements RxMongoEntity {
ObjectId id
String description
boolean done
}
```

Start by reproducing the example application with Grails 3.2.0 RC1, the rx-mongodb feature, and `create-domain-resource myapp.Todo`. Check the generated Todo resource at `/todo` and the reported transaction-manager exception; done means the endpoint serves the Todo list without that error.

Written by the indexing model from the issue text.