Expanded excludes for extmodules workflows

[ericblau]

Currently (as of 1.7.1), extmodules workflows can be configured to exclude modules from being published by specifying a list (in the workflow configuration) of exact module names to ignore.
You can also put "IPF_FLAGS:NOPUBLISH" into any module file, and IPF will ignore that file.

However, it might be nice to be able to specify subdirectories to ignore, or perhaps support wildcards. Thus, this issue is a container to memorialize that improving software publishing excludes should be further pursued.