wifi: Move legacy HAL implementation

Changes in the CL:
1. Move the legacy HAL implementation from
"frameworks/opt/net/wifi/wifi_hal_legacy" to
"hardware/interfaces/wifi/1.0/default".
2. Renamed the .rc file and the module name in makefile to
conform to the HIDL style guide.

Files renamed from:
wifi_hal_service.cpp/h -> wifi.cpp/h
wifi_chip_service.cpp/h -> wifi_chip.cpp/h
main.cpp -> service

Bug: 31821133
Test: mmma -j32 hardware/interfaces/wifi/1.0/default
Change-Id: I5e65e2fdb5596346bde6963588031dcea42d633a