Lookup validation - Ignore local=true

[0xC0FFEEEE]

We've modified a couple of our Azure AD rules to use local=true as the ESCU searches fail on our cloud ES search head.

After converting our savedsearches.conf search back to YAML and running validation over the rules, contentctl complains that the local=true lookup doesn't exist. This simple change adds an an additional non-capture group to ignore this option.

[pyth0n1c]

I think we will have to make this (and the larger lookup matching regex) a bit more robust against reordering parameters: https://github.com/splunk/contentctl/pull/82/files#diff-4ade9637ffaa744323786af0102ad18f3f46ea560f36f867aba8cc66c05d171aR51
It will be a fairly complicated regex and will take a bit of experimentation. I'll reach out to someone on my team who is far better at regexes than I am to refine it :)

[pyth0n1c]

This has turned into a much larger PR than I originally thought. We will work towards supporting things like reordering, inputlookup, and outputlook as well.
As such, I am closing this one out in favor of the new one: #274