rename jooby-hbm module to jooby-hbm4

latest version of hibernate is 5... will rename existing module to hbm4

next version requires a `pom.xml` change:

``` xml
<dependency>
  <groupId>org.jooby</groupId>
  <artifactId>jooby-hbm</artifactId>
</dependency>
```

will be:

``` xml
<dependency>
  <groupId>org.jooby</groupId>
  <artifactId>jooby-hbm4</artifactId>
</dependency>
```
