Adds a library to run classic Bluetooth A2DP source (output) audio from
the PicoW. Simple example showing operation and callbacks.
Factor out multiple BT lock/unlock and place in the PicoW variant files.
* Update to Pico-SDK v1.5
* Hook in pico_rand, use ioctl to set ipv6 allmulti
* Move into PicoSDK LWIP mutex, hack timer sizes
* Utilize much of the PicoSDK infrastructure for WiFi
* Add WiFi::begin(ssid, pass, bssid)
* WiFiMulti to use BSSID, make more robust
WiFiMulti will now be more aggressive and try all matching SSIDs, in order
of RSSI, using the BSSID to identify individual APs in a mesh.
Before, if the highest RSSI AP didn't connect, it would fail immediately.
Now, it will go down the list, ordered by RSSI, to attempt to get a link.
* Add Bluetooth support from Pico-SDK
Able to build and run the HID Keyboard Demo from the Arduino IDE, almost
as-is.
Will probably need to make BT configurable. Enabling BT on a plain WiFi
sketch uses 50KB of flash and 16KB of RAM even if no BT is used.
* Separate picow libs, BT through menus, example
Build normal Pico.a and 4 different options for PicoW IP/BT configuration.
Use IP=>IP/Bluetooth menu to select between options.
* CMakefile rationalization
* Move BT TLV(pairing) out of last 2 flash sectors
The pairing keys for BT are stored at the end of flash by default, but
we use the last sector of flash for EPROM and the penultimate one for
the filesystem. Overwriting those in BT could cause some real exciting
crashes down the line.
Move the store to an app-build specific address using a dummy const
array to allocate space in the application image itself.
* PicoBluetoothHID with BT Mouse, Joystick, Keyboard
Add simple Bluetooth Classic HID helper function and port the existing
USB HID devices to it. Port their examples.
* Protect BT key storage from multicore
* Add short-n-sweet Bluetooth documents
* Add Bluetooth Serial port library
* Turn off BT when the BT libraries exit
