Update template ovls

[uablrek]

• remove the never-used dbg() function
• Refactor cmd_env(), and call it by default
• Refactor cmd_test()
• Add --log=, or export __log=. To use > $log still work, but is considered obsolete
• Work-around to allow default setting of $__nvm in cmd_env()
• Export options specified on the command line ($long_opts)
• Fix indentation
• Template for the test_default() function. Encouraged to simplify CI
• Handle --cni=. Also encouraged to simplify CI
• Special handling of --cni=cilium

[uablrek]

Hold this for some time. I want to update documentation in ovl/test.