Added initial code for gtest

Added initial code for gtest

- Without Wi-Fi Mesh feature
 Overall coverage rate:
 lines......: 80.5% (1213 of 1506 lines)
 functions..: 84.0% (121 of 144 functions)

- Without Wi-Fi Mesh feature but without Wi-Fi chip
 Overall coverage rate:
 lines......: 85.6% (1327 of 1551 lines)
 functions..: 91.1% (133 of 146 functions)

- With Wi-Fi Mesh feature and without peer nodes
 Overall coverage rate:
 lines......: 94.9% (1472 of 1551 lines)
 functions..: 95.9% (140 of 146 functions)

- With Wi-Fi Mesh feature and with 1 more peer nodes
 Overall coverage rate:
 lines......: 97.1% (1506 of 1551 lines)
 functions..: 98.6% (144 of 146 functions)

Change-Id: I17efc29c1933a015b418b7cb47b5afd3ad3ba431
Signed-off-by: Abhishek Sansanwal <abhishek.s94@samsung.com>
Signed-off-by: saerome.kim <saerome.kim@samsung.com>
Signed-off-by: Nishant Chaprana <n.chaprana@samsung.com>
Signed-off-by: Kshitiz <kshitiz.b@samsung.com>