Support for <title render="[value]"> in <unittitle>

[mmmmcode]

ArcLight currently displays the contents of <title> tags contained in <unittitle> tags, but does not style contents as specified in the "render" attributes in either the component view or navigation sidebar.

Example of a <unittitle> that contains the title of a brochure, which would ideally display in quotation marks

<c01 level="item">
        <did>
          <unittitle>
            <title render="doublequote">Good habits for children</title>
          </unittitle>
          <unitdate calendar="gregorian" certainty="approximate" datechar="creation" era="ce"
            normal="1950/1959" type="inclusive">approximately 1950s</unitdate>
          <container label="Mixed Materials" type="box">1</container>
        </did>
</c01>

Another example where a <unittitle> contains the title of a magazine, which would ideally display in italics:

<c02 level="file">
        <did>
          <unittitle>
            <title render="italic">BUST</title>, issues 1-15
          </unittitle>
          <container label="Mixed Materials" type="box">1A</container>
        </did>
</c02>

[crugas]

We also do this for <title> and <unittitle> elements, adding bold, italics, etc., and would like them to render. Here's a list of the possible values that could be assigned to the render attribute:

altrender, bold, bolddoublequote, bolditalic, boldsinglequote, boldsmcaps, boldunderline, doublequote, italic, nonproport, singlequote, smcaps, sub, super, underline

Source: https://www.loc.gov/ead/tglib/elements/title.html.

NOTE: the EAD2002 tag library for <unittitle> does not list render as an attribute and I'm not sure why (https://www.loc.gov/ead/tglib/elements/unittitle.html).

[mmmmcode]

@crugas render is not listed as a unittitle attribute because it is not valid ead (or vice versa, I suppose)