[Build] Add short compressed build description (#3262)

[TD-er]

See #3262

Outputs Tffff:e000:Pe800:24:4400:(3):800:
Equivalent to:

    "CONTROLLER_SET_ALL",
    "NOTIFIER_SET_NONE",
    "PLUGIN_SET_ONLY_SWITCH",
    "USES_P001",  # Switch
    "USES_P002",  # ADC
    "USES_P004",  # Dallas DS18b20
    "USES_P100",  # Pulse Counter - DS2423
    "USES_C016",  # Cache Controller
    "USES_C018",  # TTN/RN2483
    "USES_C015",  # TTN/RN2483

Still missing Notifier, CPU, flash size.

[tonhuisman]

I think this would also need a Python counterpart, to define the filename before the compile is started?

[tonhuisman]

Wouldn't it be more natural to first list the 'P' plugins bitmap, then the 'T' controllers bitmap and then the 'N' notifications bitmap? (to be implemented). I think most users will first look at the plugins before looking at the controllers, but that may just be me.

[TD-er]

In size it wouldn't matter and in decoding probably also makes no difference.
But I doubt someone will try to read the filename encoding.
So we should make some decoder where it is most practical.

Maybe a JS piece of code somewhere online where a user can decode the string into readable form.

[tonhuisman]

Been chewing a bit in the back of my mind for a couple of weeks now, and it feels more and more like a way to go forward. It may need a way to include the 'other' compile-time flags like FEATURE_SD, FEATURE_I2CMULTIPLEXER, FEATURE_ADD_VCC etc. Maybe some of the .h files (custom.h , define_plugin_sets.h) should be parsed to determine the actual features that will be included, not forgetting the features set from the .py scripts. Found pypreprocessor that could possibly handle that (after some adjustments to make it C-preprocessor compatible, as it now has its own dialect, and doesn't yet support #if defined(XX), comparisons, etc.).

[TD-er]

Nee to add a bitmap too for all the FEATURE_xxx defines.

[tonhuisman]

These are the (global) FEATURE_(flags) I found after converting all non-plugin, non-controller, non-Notifier USE_/USES_ settings:

Feature flags: (Alphabetic order)
---------------------------------
FEATURE_ADC_VCC
FEATURE_ARDUINO_OTA
FEATURE_BLYNK
FEATURE_CHART_JS
FEATURE_CUSTOM_PROVISIONING
FEATURE_DNS_SERVER
FEATURE_DOMOTICZ
FEATURE_DOWNLOAD
FEATURE_ESPEASY_P2P
FEATURE_ETHERNET
FEATURE_ETHERNET
FEATURE_EXT_RTC
FEATURE_FHEM
FEATURE_HOMEASSISTANT_OPENHAB
FEATURE_I2CMULTIPLEXER
FEATURE_I2C_DEVICE_SCAN
FEATURE_MDNS
FEATURE_MODBUS
FEATURE_MQTT
FEATURE_NON_STANDARD_24_TASKS
FEATURE_NOTIFIER
FEATURE_PACKED_RAW_DATA
FEATURE_PLUGIN_STATS
FEATURE_RTTTL
FEATURE_SD
FEATURE_SERVO
FEATURE_SETTINGS_ARCHIVE
FEATURE_SSDP
FEATURE_TIMING_STATS
FEATURE_TOOLTIPS
FEATURE_TRIGONOMETRIC_FUNCTIONS_RULES
// FEATURE_REPORTING