Refactor `update-template-ubuntu.sh` and add `update-template-debian.sh` #5983

Job	Run time
Colima (v0.6.5)	6m 47s
Integration tests	12m 44s
Integration tests (on Linux) (alpine.yaml)	6m 32s
Lints	1m 59s
Integration tests (on Linux) (debian.yaml)	6m 10s
Spell check	11s
Integration tests (on Linux) (fedora.yaml)	6m 33s
Unit tests (1.22.x)	52s
Integration tests (on Linux) (opensuse.yaml)	7m 40s
Upgrade test (v0.15.1)	11m 22s
Unit tests (1.23.x)	4m 34s
Integration tests (on Linux) (docker.yaml)	17m 9s
VMNet test	12m 17s
Integration tests (on Linux) (../hack/test-templates/alpine-iso-9p-writable.yaml)	5m 45s
vz (default.yaml)	10m 58s
Integration tests (on Linux) (../hack/test-templates/net-user-v2.yaml)	7m 29s
vz (fedora.yaml)	9m 52s
Integration tests (on Linux) (../hack/test-templates/test-misc.yaml)	20m 7s
Windows tests	1m 1s
	2h 30m 2s

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