Fix build without CS_ENABLE_STDIO

Get rid of trigraphs in string defaults when genereating config

CL: Get rid of trigraphs in string defaults when genereating config

Fix serve_core.py when there are no tasks

Update bootloader binaries to 1.5.0

CL: Update bootloader binaries to 1.5.0

PUBLISHED_FROM=ade588df465e359538e1ccd4fc4219e24e7d7e9d

Update bootloader binaries to 1.5.0

CL: Update bootloader binaries to 1.5.0

PUBLISHED_FROM=ade588df465e359538e1ccd4fc4219e24e7d7e9d

Fix pull-up setting on STM32

CL: Fix pull-up setting on STM32

PUBLISHED_FROM=d0e12a8068d247d608e24c49ccb4d61fb62127bf

Allow getting and setting config at different levels

Also add arguments to `Config.Set` RPC:
 * `level` (int, default: 9 [user]) - make changes at the given level.
 * `save` (bool, default: true) - save the changes
 * `try_once` (bool, default: false) - when saving, make the changes only apply on next boot.
 * `reboot` (bool, default: false) - reboot after saving.

`Config.Save` is now optional and obsolete.

Make `mos license` save to level 1 by default to avoid blowing away license on user config reset.

CL: Allow getting and setting config at different levels

PUBLISHED_FROM=16dd8c6059bf4e347e9df71ace4e955100510e6e

Add mgos_uptime_micros(), fix sleep issues on CC32x and STM32

`mgos_uptime_micros()` provides a reliable, microsecond-accurate monotonic counter on all our supported platforms:

 * On ESP32 we have esp_timer_get_time()
 * On ESP8266 we have system_get_time() (plus overflow handling)
 * On ARM-based platforms we use FreeRTOS xTaskGetTickCount() + SYSTICK for fractional ticks

CL: Add mgos_uptime_micros(), fix sleep issues on CC32x and STM32

PUBLISHED_FROM=fb548dc351b24de0f0ceb1b0f974be3b495264d3

Clean up config validation API

CL: none

PUBLISHED_FROM=c19078c0ce069e3866ae0eb7360ddc9686b83914

Add encoding when opening text files

CL: none

PUBLISHED_FROM=dbfcae888cfb1f7dcfb5ac1ed9b18947f838a082