fix(packaging): drop unsupported ConditionEnvironment from cloud-init units on systemd < 246

[blackboxsw]

Focal's systemd 245.4 doesn't have support for ConditionEnvironment keys in units, it was introduced in systemd 246. Drop these keys from cloud-init units/targets to avoid warnings from systemctl status and journalctl about systemd ignoring those keys.

rebase merge individual commits

primary funtional commit

    fix(packaging): drop unsupported ConditionEnvironment keys from units
    
    Focal is based on systemd 245.5 which doesn't support
    ConditionEnvironment keys in Units. This feature was introduced in
    systemd 246. As a result, journalctl and systemctl status cloud-init
    will show warnings about systemd ignoring this key in various cloud-init
    units. Apply a quilt patch for focal-only which will drop this ignored
    key from our units/targets.

Additional Context

Test Steps

lxc launch ubuntu-daily/focal test-f 
lxc exec test-f -- cloud-init status --wait
# See warning messages from systemd about unsupported config keys 
lxc exex test-f -- journalctl -b 0 | grep ConditionEnvironment

Checklist

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[TheRealFalcon]

LGTM!