[Thread] move off joiner start from timer task

[bukepo]

This commit fixes #2188 by starting joiner in Thread task.

[github-actions]

Size increase report for "gn_nrf-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

[github-actions]

Size increase report for "gn_linux-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

[github-actions]

Size increase report for "nrf-example-build"

File	Section	File	VM
chip-nrf52840-lock-example.out	.text	72	72
chip-nrf52840-lock-example.out	.data	4	4
chip-nrf52840-lock-example.out	[LOAD #2 [RW]]	0	4

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-nrf52840-lock-example.out and ./pull_artifact/chip-nrf52840-lock-example.out:

sections,vmsize,filesize
.debug_info,0,356
.debug_str,0,321
.text,72,72
.symtab,0,64
.debug_loc,0,50
.debug_abbrev,0,47
.strtab,0,15
.debug_aranges,0,8
.data,4,4
.debug_frame,0,4
[LOAD #2 [RW]],4,0
.debug_ranges,0,-16
[Unmapped],0,-73

[github-actions]

Size increase report for "nrfconnect-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-nrf52840-lock-example.elf and ./pull_artifact/chip-nrf52840-lock-example.elf:

sections,vmsize,filesize

[github-actions]

Size increase report for "linux-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-standalone-demo.out and ./pull_artifact/chip-standalone-demo.out:

sections,vmsize,filesize

[github-actions]

Size increase report for "esp32-example-build"

File	Section	File	VM

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-wifi-echo.elf and ./pull_artifact/chip-wifi-echo.elf:

sections,vmsize,filesize

[mspang]

I was thinking we'd move even more, and just have a queue send in the timer. That's what AppTask does for example. But this is definitely an improvement.