When using the Azure data source, frames are not guaranteed to be
unique to each boot.  Instead of splitting boot records when any event
is seen more than once, do so whenever the start of `init-local` stage
is found (and records have already been processed).

Signed-off-by: Chris Patterson <cpatterson@microsoft.com>

Sponsored by: FreeBSD Foundation

As we do not support python2 anymore, we can remove those 8 chars.

Add tox target for tracing for resource leaks, fix some leaks

- Remove references and dead code to Xenial, Eoan, Python < 3.7
- cc_ubuntu_drivers: Use python3-debconf instead of shell script
- add integration test for ubuntu_drivers
- bump pycloudlib for OCI subnet/jammy fixes

upstream cloud-init not longer publishes to distribution
versions which support upstart.

Trusty has not been receiving cloud-init updates since
0.7.5 and Xenial stopped getting updates as version 21.1.

Even though Ubuntu Xenial's default init system is systemd
there was still an option for folks to launch amd maintain
images which relied on upstart. Now that Xenial no longer has
updates from upstream cloud-init we can drop all upstart
support.

Old Fedora and RHEL releases which use upstart are also not
receiving cloud-init updates from tip of main.

Expect that "systemctl" is found in the PATH. Using the '/bin' prefix
is very distribution specific. A number of distributions are moving
all executables from '/' to '/usr'.

Applied Black and isort, fixed any linting issues, updated tox.ini
and CI.

This attempts to standardize unit test file location under test/unittests/
such that any source file located at cloudinit/path/to/file.py may have a
corresponding unit test file at test/unittests/path/to/test_file.py.

Noteworthy Comments:
====================
Four different duplicate test files existed:
test_{gpg,util,cc_mounts,cc_resolv_conf}.py
Each of these duplicate file pairs has been merged together. This is a
break in git history for these files.

The test suite appears to have a dependency on test order. Changing test
order causes some tests to fail. This should be rectified, but for now
some tests have been modified in
tests/unittests/config/test_set_passwords.py.

A helper class name starts with "Test" which causes pytest to try
executing it as a test case, which then throws warnings "due to Class
having __init__()".  Silence by changing the name of the class.

# helpers.py is imported in many test files, import paths change
cloudinit/tests/helpers.py -> tests/unittests/helpers.py

# Move directories:
cloudinit/distros/tests -> tests/unittests/distros
cloudinit/cmd/devel/tests -> tests/unittests/cmd/devel
cloudinit/cmd/tests -> tests/unittests/cmd/
cloudinit/sources/helpers/tests -> tests/unittests/sources/helpers
cloudinit/sources/tests -> tests/unittests/sources
cloudinit/net/tests -> tests/unittests/net
cloudinit/config/tests -> tests/unittests/config
cloudinit/analyze/tests/ -> tests/unittests/analyze/

# Standardize tests already in tests/unittests/
test_datasource -> sources
test_distros -> distros
test_vmware -> sources/vmware
test_handler -> config        # this contains cloudconfig module tests
test_runs -> runs