Remove lttng_event_rule_tracepoint

lttng_event_rule_tracepoint is "exploded" in:
   lttng_event_rule_user_tracepoint
   lttng_event_rule_kernel_tracepoint
   lttng_event_rule_jul_logging
   lttng_event_rule_python_logging
   lttng_event_rule_log4j_logging

On the CLI front, the `--domain` option for the add-trigger is removed
since for each event rule type the domain is implicit based on the type.

`--type` accepts the following:
   kernel
   kernel:tracepoint
   kernel:kprobe
   kernel:uprobe
   syscall
     syscall:entry
     syscall:exit
     syscall:entry+exit
     syscall:*
   kernel:syscall
     kernel:syscall:entry
     kernel:syscall:exit
     kernel:syscall:entry+exit
     kernel:syscall:*
   user
   user:tracepoint
   python
   python:logging
   jul
   jul:logging
   log4j
   log4j:logging
   kprobe
   function

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I4a0489f8f2a79a2c967f5d69461bed10f40b8278