Backport of #48849. Update `.editorconfig` to make the Java settings the
default for all files, and then apply a 2-space indent to all `*.gradle`
files. Then reformat all the files.
This commit adds a new :test:fixtures:azure-fixture project which
provides a docker-compose based container that runs a AzureHttpFixture
Java class that emulates an Azure Storage service.
The logic to emulate the service is extracted from existing tests and
placed in AzureHttpHandler into the new project so that it can be
easily reused. The :plugins:repository-azure project is an example
of such utilization.
The AzureHttpFixture fixture is just a wrapper around AzureHttpHandler
and is now executed within the docker container.
The :plugins:repository-azure:qa:microsoft-azure project uses the new
test fixture and the existing AzureStorageFixture has been removed.