Allow changing WiFi Hostname at compile time from user_config_override.h

[ascillato]

Description:

This small PR adds the option to allow changing the WiFi Hostname at compile time from user_config_override.h.

Usage:

• Add in user_config_override.h file the following so the hostname can be customized at compile time:

#undef DEFAULT_WIFI_HOSTNAME
#define DEFAULT_WIFI_HOSTNAME  "MyDevice"

Notes:

• The default value is "%s-%04d" which expands to <MQTT_TOPIC>-<last 4 decimal chars of MAC address>
• This PR does not change the FLASH or RAM usage.

Related issue (if applicable): NA

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.6
• The code change is tested and works with Tasmota core ESP32 V.3.0.0
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass

[Jason2866]

LGTM

[sfromis]

You can have hostname included in the build without a new #define, by using the regular Hostname command in USER_BACKLOG. Commands given there will be executed first boot with new settings.

[barbudor]

There's a lot of consts for which I would have loved to do that in the past but I was so afraid of changing that order... 🥶
Thank you for your bravery @ascillato 👍

[ascillato]

@sfromis Hi, you are right with that. In fact, I was using that in my devices at home, but there is the issue with the user backlog approach (for this case in particular) that takes time and require a restart making other issues like the WiFi AP name (which uses the Hostname) not taking the change right away showing the previous naming. With this simple change, which adds no extra code to the Firmware, we can allow the user to set the HOSTNAME (or a custom template of the hostname like "%s-%06d") at compile time simplifing the process.

[Jason2866]

Let us merge and see what happens ;-)

[arendst]

Implemented differently but same result.

#define WIFI_DEFAULT_HOSTNAME  "%s-%04d"         // [Hostname] Expands to <MQTT_TOPIC>-<last 4 decimal chars of MAC address>

[ascillato]

Awesome. Thanks!