PD Notification Support to Links

These code changes will allow PD notifications to include links. This change itself doesn't make this happen though. The notifications themselves need to be updated to create the links. Locally I modified 'Proposal submitted to sponsor after routing' to read as follows.
```
The Proposal <a title="" target="_self" href="{DOCUMENT_PREFIX}/kew/DocHandler.do?command=displayDocSearchView&amp;docId={DOCUMENT_NUMBER}">{PROPOSAL_NUMBER}</a> has been submitted to sponsor.<br/>The institute proposal number is <a title="" target="_self" href="{DOCUMENT_PREFIX}/kew/DocHandler.do?command=displayDocSearchView&amp;docId={INSTITUTIONAL_PROPOSAL_DOC_NBR}">{INSTITUTIONAL_PROPOSAL_NUMBER}</a>.  
```