Ensure image URL is properly encoded

[Vitaliy-1]

Related to: https://forum.pkp.sfu.ca/t/jatsparserplugin-and-oldgregg-after-upgrade-to-3-2-1-2/64498/11

The Texture plugin doesn't escape spaces in the URI of the image in the JATS XML output. To reproduce:

1. Create new JATS XML file
2. Open with Texture
3. Create a new Figure, upload a file with a filename that contains spaces, e.g. fig 1.jpg as per forum thread.
4. Save the file and explore tags related to a new figure:

   <graphic id="graphic-2b9ee4ad70b4c56ec056012bf94bd7fa" mimetype="image" mime-subtype="jpeg" xlink:href="fig 1.jpg"/>

   according to the JATS XML specification: https://jats.nlm.nih.gov/publishing/tag-library/1.3d1/attribute/xlink-href.html

As specified in XML Linking Language (XLink) Version 1.0, the value of an @xlink:href must be a valid URI.

if considering encoded one: xlink:href="fig%201.jpg

• Escape URLs in the HTML output
• Should/can it be escaped in Texture?