Include CodeQL code scanning to repo's

[stijnmoreels]

Is your feature related to a problem? Please describe.
Currently, we don't have any code scanning capabilities on our code.

What solution do you propose?
Add GitHub's CodeQL code scanning to the repo's.

• Security (@stijnmoreels chore: add CodeQL code scanning arcus.security#337)
• Messaging (@stijnmoreels chore: add codeql code scanning arcus.messaging#255)
• EventGrid (@stijnmoreels chore: add codeql code scanning arcus.eventgrid#223)
• Templates (@stijnmoreels chore: add codeql code scanning arcus.templates#552)
• WebAPI (@stijnmoreels chore: add codeql scanning arcus.webapi#313)
• Observability (@stijnmoreels chore: add CodeQL code analysis arcus.observability#350)
• BackgroundJobs (@stijnmoreels chore: add codeql code scanning arcus.backgroundjobs#123)
• Testing (@stijnmoreels chore: add codeql code scanning arcus.testing#60)

Discussed in #195

^{Originally posted by stijnmoreels March 11, 2022}
Could we consider adding GitHub code-scanning to our Arcus repositories?
Seems like a good thing that the umbrella code is also verified in every possible way.

[stijnmoreels]

All updated! 🥳