binder: Implement iface methods

Implement the following iface methods:
1. Reassociate
2. Reconnect
3. Disconnct

BUG: 30093041
Change-Id: I83a527a06c89f05e693212c536f21494c678843e
TEST: Writing new tests in |wpa_supplicant_binder_test|
Signed-off-by: Roshan Pius <rpius@google.com>
3 files changed