chore: add vendor folder

[reubenmiller]

Add a vendor folder for all of the 3rd party dependencies so other tooling (such as yocto) can parse the licensing information.

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
12	0	0	12	100	4m19.391431s

Passed Tests

Name	⏱️ Duration	Suite
Update to tedge-container-plugin-ng	28.199 s	Installation
Get Configuration	5.306 s	Operations
Install/uninstall container-group package	15.105 s	Operations
Install container-group with multiple files - app1	35.983 s	Operations
Install container-group with multiple files - app2	10.057 s	Operations
Install/uninstall container package	14.874 s	Operations
Install/uninstall container package from file	11.815 s	Operations
Manual container creation/deletion	16.031 s	Operations
Manual container creation/deletion with error on run	7.839 s	Operations
Manual container created and then killed	10.395 s	Operations
Service status	23.475 s	Telemetry-Main
Sends measurements	80.314 s	Telemetry-Main