Update PlatformIO build scripts (espressif#7200) (#150) (#152)

This update includes the following:

- Implemented an additional build step that produces an adjusted bootloader image with updated headers
  according to  selected flash mode and size values. This step is only executed for debugging or uploading
  via debug probes.

- Implemented a basic mechanism to dynamically add an extra UF2 bootloader image if corresponding
  partition is selected (e.g. for Adafruit targets)

- Minor code formatting

Co-authored-by: Valerii Koval <valeros@users.noreply.github.com>

Co-authored-by: Valerii Koval <valeros@users.noreply.github.com>