Add template blacklist and whitelist

[dirgim]

This change adds os_template_whitelist and os_template_blacklist group variables (lists) that define which templates will be included/skipped according to these rules:

• All the template names in os_template_blacklist will be skipped
• If os_template_whitelist is defined, only the template names listed in it will be built
• If a template name shows up in both os_template_whitelist and os_template_blacklist, it will be skipped, as the blacklist takes precedence

Both lists are empty by default, meaning that all the templates in the os_template_dir will be built.

[johnbieren]

[test]

[joejstuart]

Is there an easy way to see what templates can be built?

[dirgim]

@joejstuart it uses the template name stated in the yaml, so some advanced grepping might help.
Or maybe using the oc process -f {{ template_file.path }} | jq '.items[1].metadata.labels.template' command on each file.

[dirgim]

[test]

[joejstuart]

@dirgim Sounds good. Thanks for the explanation.

[arilivigni]

LGTM

[psiroky]

LGTM