[btp] align code to the specification

[LuDuda]

Problem

• BTP fragment size is limited to 128 (244 in the spec - which works best with ATT_MTU >= 247)
• BTP in version 4 is not supported (required by the spec)
• The maximum BTP fragment size for Peripheral TX is always limited to 20B - regardless of ATT_MTU value
• Handshake frame has invalid first byte 0x6e (0x65 in the spec)

Change overview

Fixed all the above issues and increase the default BTP window size to speed up the commissioning process.
The overall commissioning time depends on BLE connection parameters, but can be done in under 2 seconds (tested with nRF Connect platform).

Testing

Tested manually with Python CHIP controller and Android CHIP Tool against nRF Connect platform. Inspected fields in BTP payload using BLE Sniffer.

[github-actions]

Size increase report for "gn_qpg-example-build" from 257d179

File	Section	File	VM
chip-qpg6100-lighting-example.out	.text	-32	-32

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-qpg6100-lighting-example.out.map and ./pull_artifact/chip-qpg6100-lighting-example.out.map:

BLOAT EXECUTION FAILED WITH CODE 1:
bloaty: unknown file type for file './pull_artifact/chip-qpg6100-lighting-example.out.map'

Comparing ./master_artifact/chip-qpg6100-lighting-example.out and ./pull_artifact/chip-qpg6100-lighting-example.out:

sections,vmsize,filesize
[Unmapped],0,32
.debug_ranges,0,8
.debug_loc,0,6
.debug_frame,0,-4
.text,-32,-32
.debug_str,0,-65
.debug_line,0,-74
.debug_info,0,-379

[github-actions]

Size increase report for "esp32-example-build" from 257d179

File	Section	File	VM
chip-all-clusters-app.elf	.flash.text	-48	-48

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize
.debug_loc,0,107
[Unmapped],0,48
.debug_ranges,0,8
.riscv.attributes,0,-1
.flash.text,-48,-48
.debug_str,0,-64
.debug_line,0,-175
.debug_info,0,-323

[github-actions]

Size increase report for "nrfconnect-example-build" from 257d179

File	Section	File	VM
chip-lock.elf	text	-32	-32
chip-shell.elf	device_handles	-8	-8
chip-shell.elf	text	-24	-24

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-lock.elf and ./pull_artifact/chip-lock.elf:

sections,vmsize,filesize
.debug_ranges,0,8
.debug_frame,0,-4
text,-32,-32
.debug_str,0,-64
.debug_line,0,-73
.debug_loc,0,-108
.debug_info,0,-367

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
.debug_loc,0,52
.debug_ranges,0,8
.debug_frame,0,-4
device_handles,-8,-8
text,-24,-24
.debug_str,0,-64
.debug_line,0,-73
.debug_info,0,-247