* master:
app_main: Return type to void
wifi: move type definitions into separate header file
wifi: use default esp_event_send handler in WIFI_INIT_CONFIG_DEFAULT
nvs: Remove flash layout arguments from nvs_init()
Add contributor agreement, update CONTRIBUTING file
Update http_request & https_request examples for new startup flow
Add very simple "hello world" & "blink" examples
Build examples out-of-tree as part of CI process
Examples: Use event groups for waiting until WiFi is associated & ESP has IP
BT example: Enable BT stack in config by default
BT: Relink component on new BT library, auto-initialise submodule if missing
Documentation: Add contributor guide, expand README & add an examples README
Update gitignore for examples
examples: Add https_request example
mbedtls: Add some initial menuconfig options
examples: HTTP request example
component/esp32: udpate wifi lib
component/esp32: modify bool argument name from enable to en
component/esp32: adjust some APIs
esptool: Bump upstream revision
87091e10fe