update page/cover identification logic to also look for jpegs
provide access to ARK URI via dc for all local fedora digital objects
add page/volume display label methods for use in page titles and twitter/facebook metadata

[#76531236 #75230428]
tweaks & minor cleanup to volume twitter/opengraph info

[#75230428 #76531236]
tweak twitter/opengraph metadata; use twitter photo card

[#76531236 #75230428]
tweak twitter/opengraph metadata; use twitter gallery card

[#76531236 #75230428]