tests: Bluetooth: BR: Add test suite gap_client

IUT works as a Bluetooth GAP Client. The peer device (tester) is
configured to respond to inquiries and process connection requests.

Add tests to verify GAP client functionality for inquiry, connection,
and disconnection scenarios.

In the test suite, there are six test cases:
Case 1: General Inquiry followed by Connection and Active Disconnection.
Verifies that DUT can perform general inquiry, establish connection, and
actively disconnect from tester.
Case 2: General Inquiry followed by Connection and Passive
Disconnection. Verifies that DUT can perform general inquiry, establish
connection, and handle disconnection initiated by tester.
Case 3: General Inquiry followed by Rejected Connection Request.
Verifies that DUT can perform general inquiry and handle connection
rejection from tester.
Case 4: Limited Inquiry followed by Connection and Active Disconnection.
Verifies that DUT can perform limited inquiry, establish connection, and
actively disconnect from tester.
Case 5: Limited Inquiry followed by Connection and Passive
Disconnection. Verifies that DUT can perform limited inquiry, establish
connection, and handle disconnection initiated by tester.
Case 6: Limited Inquiry followed by Rejected Connection Request.
Verifies that DUT can perform limited inquiry and handle connection
rejection from tester.

Signed-off-by: Jiawei Yang <jiawei.yang_1@nxp.com>