init: Prevent copying of Service objects

Service objects have external state (the child process) and hence must
not be duplicated. Disable the copy constructor and the assignment
operator to prevent that these objects get duplicated accidentally.

Bug: 213617178
Change-Id: Ia5391154b94eca7f12be69eabcdf3f173fc06452
Signed-off-by: Bart Van Assche <bvanassche@google.com>