Feature: Send enpoint for non-terminal using implicit NTA
- enable send endpoint targeting non-terminals (single, optional, and list) by generating an NTA whose equations comprises their value
- requires #35 #34 #33
DSL:
```
send Model.Single;
send Model.Maybe;
send Model.Multiple;
send A;
```
Generated Aspect:
```java
syn nta A Model._ragconnect_send_Single() = getSingle();
syn nta Opt<A> Model._ragconnect_send_Maybe() = getMaybe();
syn nta JastAddList<A> Model._ragconnect_send_Multiple() = geMultiple();
syn nta A A._ragconnect_send_self() = this;
```
issue