* add esp-phy-lib submodule
* move libphy.a and phy_init.c from esp_wifi to esp_phy
* move librtc.a from esp_wifi to esp_phy
* move libbtbb.a from bt to esp_phy
* corresponding updates to build system
1. Improve WiFi throughput in some Classic BT scienarios(idle, inquire scan,
connected, sniff, a2dp pause, etc).
2. Support WiFi + Classic BT + BLE mesh coexistence scienario.
3. Improve WiFi scan and connect succeed ratio in coexistence scienario.
4. Do not support to choose software coexistence preference anymore for it is
determined according to coexistence scienario automatically.
components/lwip: increase TCP send buffer and receive window limitation when TCP window scale is enabled
components/ble_mesh: Fix some bugs about ble mesh
1. fix send acl pkt after ble have sent terminate ind modify min adv interval to 10ms.