Enable url_norm by default

[anjackson]

In testing it seems the default config does not enable the url_norm field, which SolrWayback needs. It's a pretty useful field anyway, so I suggest we switch it on by default.

[anjackson]

It seems that the current logic is that the normalised URL is stored if we configure the links to be stored in normalised form:

webarchive-discovery/warc-indexer/src/main/java/uk/bl/wa/indexer/WARCIndexer.java

Lines 181 to 183 in 02ee73e

	addNormalisedURL = conf.hasPath(HtmlFeatureParser.CONF_LINKS_NORMALISE) ?
	conf.getBoolean(HtmlFeatureParser.CONF_LINKS_NORMALISE) :
	HtmlFeatureParser.DEFAULT_LINKS_NORMALISE;

It's not immediately obvious to me why these two separate fields are being coupled in this way, but the upshot is that implementing this ticket means changing this line:

webarchive-discovery/warc-indexer/src/main/resources/reference.conf

Line 82 in 81acb31

"normalise" : false,

Given the two fields are coupled, does this mean we need to enable resource-level link extraction for this to be any use? I think not?

webarchive-discovery/warc-indexer/src/main/resources/reference.conf

Line 83 in 81acb31

"resources" : false,

[anjackson]

i.e. is

                "linked" : {
                    "normalise" : true,
                    "resources" : false,
                    "hosts" : true,
                    "domains" : true,
                    "images" : true
                },

a valid configuration?