Implement search query quote parsing

[malberts]

Follow-up to #31

Quote parsing is not implemented yet.

The skipped test added in #70 expected quotes around each individual OR value, to allow for multiple quoted values:
haswbfacet:P42="foo bar"|second|"third value"

However, the quote parsing that returns $quotedValue in HasWbFacetFeature::doApply() (via SimpleKeywordFeature) seems to expect quotes for the entire keyword value:
haswbfacet:"P42=foo bar|second|third value"

[malberts]

If we make HasWbFacetFeature handle quotes as per the example test case, then our keyword will behave slightly differently compared to haswbstatement. However, that might not be an issue, since our OR handling is already different (P42=foo|bar|baz vs P42=foo|P42=bar|P42=baz).

[JeroenDeDauw]

I do not have a product-level preference for the quotation form, both seem viable enough, and we generate the search string via the UI anyway, so it's not central to the UX. So whatever is easier to implement, or up to the implementer