Restore support for the include/pattern syntax.

[jpountz]

Closes #22933

[jpountz]

@markharwood Would you mind reviewing this PR?

[markharwood]

Just tried this regex which works OK:

GET test/_search
{
	"size":0,
	"aggs":{
		"terms":{
			"terms":{
				"field":"foo.keyword",
				"include":"b.*",                
				"exclude":"a.*"				
			}
		}
	}
}

.. but this equivalent syntax fails to parse:

GET test/_search
{
	"size":0,
	"aggs":{
		"terms":{
			"terms":{
				"field":"foo.keyword",
				"include":{
					"pattern":"ba.*"                    
				},
				"exclude":{ 
					"pattern":"a.*"
				}
			}
		}
	}
}

[jpountz]

Thanks @markharwood I should have been more surprised that tests passed on the first time that I ran them, I probably ran gradle from the wrong directory, tests were completely broken! :) I just pushed a new commit that should fix it.

[markharwood]

Maybe throw an exception here if partition criteria supplied?
Partitioning not supported when using regex-based filtering.

[jpountz]

good point

[jpountz]

@markharwood Can you give it another look?

[markharwood]

LGTM