Remove the explicit requirement for servlet API on spring-jersey

In `SpringComponentProvider` it makes an explicit reference to `ServletContext.class`

```
ServletContext sc = injectionManager.getInstance(ServletContext.class);

if (sc != null) {
// servlet container
ctx = WebApplicationContextUtils.getWebApplicationContext(sc);
```

However, we should be able to embed Jersey with Spring on a non-servlet context. I tried to remove it myself, but I didn't want to recreate the other parts of it like the AutowiredInjectResolver but using the ext package forces the provider to be loaded.