[linux] Add GDBus support in PlatformMgr to drive DBUS communication.

[yufengwangca]

Problem
Extend PlatformMgr to allow service share DBus connection.
Need a consistent way to register such services to drive DBUS in a common way

Summary of Changes

• Add GDBus support in PlatformMgr to drive DBUS: Thread, BLE, WiFi.
• Add dedicated I/O thread for DBUS.

fixes #<1084>

[turon]

LGTM 👍

[mspang]

git fetch [email protected]:project-chip/connectedhomeip.git
git merge FETCH_HEAD

git fetch [email protected]:mspang/connectedhomeip.git cebf49f
git cherry-pick FETCH_HEAD

[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

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_macro,0,1
[Unmapped],0,-1

[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
.debug_macro,0,1
[Unmapped],0,-1

[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

[turon]

Needs a two more official approvers. @saurabhst? @BroderickCarlin? @andy31415?