Support for multiple VTEP MAC deletion methods

The patch adds several deletion methods, distinguished by whether
the method affects the first or all found MAC entries that match
the method's search pattern.

Also modifies the names of certain methods to enhance the naming
consistency, cleans up redundant code and adds JavaDoc for some
VTEP methods.

The affected MAC VTEP methods have been unit tested manually against
a VTEP emulator.

Signed-off-by: Alex Bikfalvi <alex.bikfalvi@midokura.com>