Apply signaling component -- rebase

[ActoryOu]

Issue #, if available:

What was changed?

• Add Signaling component and coreJSON as external projects, and update Signaling code to call APIs of component.

Why was it changed?

• To apply Signaling re-factoring component into dev branch. Signaling component is separated out as independent library. And coreJSON is used in Signaling component.

How was it changed?

• Add Signaling component and coreJSON as external projects, import it via ExternalProject_Add, and update Signaling code to call APIs of component.

What testing was done for the changes?

• Verified master demo on Ubuntu
• Verified webrtc_client_test and pass all test cases.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.20690% with 11 lines in your changes missing coverage. Please review.

Project coverage is 88.57%. Comparing base (3824226) to head (cd21c9d).

❗ Current head cd21c9d differs from pull request most recent head f060c14

Please upload reports for the commit f060c14 to get more accurate results.

Files	Patch %	Lines
src/source/Signaling/LwsApiCalls.c	96.20%	11 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2020      +/-   ##
===========================================
- Coverage    88.68%   88.57%   -0.11%     
===========================================
  Files           48       48              
  Lines        12726    12657      -69     
===========================================
- Hits         11286    11211      -75     
- Misses        1440     1446       +6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[hassanctech]

nice! very excited about this rework!