Example KPT package with subpackages

[liamfallon]

This is an example demo pacakge with two levels of subpackages, with the main package and all its subpackages deploying
separate deployments of nginx

The package has the following structure:

main--+--sub1--+--sub1sub1
      |        |
      |        +--sub1sub2
      |
      +--sub2--+--sub2sub1
               |
               +--sub2sub2

[liamfallon]

/assign @kispaljr @efiacor @Catalin-Stratulat-Ericsson @JamesMcDermott @kushnaidu @nagygergo

[Catalin-Stratulat-Ericsson]

looks good to me. will use this to debug #827 and add a test case using this package also.

[nephio-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Catalin-Stratulat-Ericsson, liamfallon

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