init: replace strdup() in parse_config()

Previously, the action, command, and service structs contained char*s
that referenced memory within the buffer returned by the strdup() of
the input buffer of parse_config.  This prevented this entire memory
region from being freed, leaking contents that would never be referenced again.

The changes to convert the previous action, command, and service
structs to C++ classes created explicit ownership of the contents within
each class in the form of std::strings.  With these changes, there are
no remaining references to the memory allocated by this strdup(), which
can now be freed.

This commit replaces the strdup() with std::vector<char> to allow for
the copied string to be freed when it goes out of scope instead of
relying on the C strdup() and free() functions.

Change-Id: Id0a5f711e33363082ba201afda6b26043998cb1c