* Plain RAK4631 should not compile EInk and TFT display code
* Add USE_TFTDISPLAY to variant files.
* Derp
* Undo the platformio.ini changes to heltec_v4
* Drop unneeded src_filter lines
---------
Co-authored-by: Jonathan Bennett <jbennett@incomsystems.biz>
Co-authored-by: Jason P <applewiz@mac.com>
Meshtastic no longer fits on the flash of the Picomputer.
Since this is a handheld, portable device, it's unlikely that people are
connecting to it via the webserver. So, disable the webserver and it fits
again:
```
Checking size .pio/build/picomputer-s3-tft/firmware.elf
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM: [=== ] 32.4% (used 106056 bytes from 327680 bytes)
Flash: [==========] 99.1% (used 3313913 bytes from 3342336 bytes)
```
Fixes: https://github.com/meshtastic/firmware/issues/7906
