Remove redondant "hello" test and move "hello-static-lib" to doc/examples

The examples are now automatically built as part of the default make target.

The "hello" test verifies that an application with statically embedded
tracepoint providers can build. This is covered by "easy-ust" in
doc/examples since we now build the examples.

Move the "hello-static-lib" test to doc/examples.

This should provide a complete and easy to understand examples to users who
wish to integrate tracepoint providers to their applications

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>