Improve CI

[samansmink]

This PR:

• cleans up CI a bit by merging the functional tests together
• adds a new workflow for tests that use an actual azure account to test against

CI is running on my fork here: https://github.com/samansmink/duckdb_azure/actions/runs/8096308985 where i also added the test credentials.

The cloud functional tests allow testing against real azure infrastructure instead of the azurite test server. Things that are now tested include:

• Creating and using a secret using the credential_chain provider with the env chain
• Testing the az cli login
• Testing the new SPN secret provider
• Confirming that the http stats of azure queries make sense

[samansmink]

Hey @quentingodeau! I added some real-world tests with the SERVICE_PRINCIPAL provider. They won't run on PR's for obvious security reasons, but at least now CI can test master branch with Azure a little bit.

If you proceed with #44 or #43, I can set up stuff in our azure test account to have things properly tested in CI here.

[carlopi]

LGTM!

Things that I though could be nice adding:

• a test showing what's the minimal needed to read from a public bucket (without setting secrets, or a minimal amount of them)
• a test showing that bucket has not been tampered (question is a bit fuzzy, but basically something saying stuff is still in a valid state after our read / unsure if there is some metric like time of last modification to the bucket available from azure )

[samansmink]

Thanks for the review @carlopi and @chrisiou. I've added:

• a test for the unauthenticated requests
• a test that checks that all files in the buckets are as expected, these are run for both azurite and azure to ensure we don't accidentally mess up the bucket.