Reduce error handling verbosity in CI tests scripts

[AjayThorve]

This PR adds a less verbose trap method, for error handling to help ensure that we capture all potential error codes in our test scripts, and works as follows:

• setting an environment variable, EXITCODE, with a default value of 0
• setting a trap statement triggered by ERR signals which will set EXITCODE=1 when any commands return a non-zero exit code

cc @ajschmidt8

[ajschmidt8]

Looks like this includes some changes from branch-23.02, but that's fine because they need to be merged to 23.04 anyway.

I've just submitted a PR to update our automation to handle that in the future.

[ajschmidt8]

/merge