Introduce https throughout, where possible

[jcowey]

Global change of http://papyri.info.+
to
https://papyri.info.+

http:// will have to remain for links to external sites, as if we replaced them, they might no longer function
this would affect particular graphic urls and e.g.

   <bibl type="online">
      <ptr target="http://163.1.169.40/cgi-bin/library?e=q-000-00---0POxy--00-0-0--0prompt-10---4------0-1l--1-en-50---20-about-2604--00031-001-0-0utfZz-8-00&amp;a=d&amp;c=POxy&amp;cl=search&amp;d=HASHfc812b71827f38121f375b"/>
   </bibl>

at
https://github.com/papyri/idp.data/blob/master/DCLP/65/64152.xml#L135-L137

[samosafuz]

Following up on this issue; please ensure that the global change includes (View in PN) links, as in the screengrab below, in addition to other canonical links.