dev/core#824 Rationalise summary part of the merge screen.

[eileenmcnaughton]

Overview

This does 3 things

1. reduces contact get queries from 3 to 1 since the 2 in the tpl layer are removed
2. adds created date to the merge summary information
3. makes it easier for extensions to replace/ extend this data (although core makes no
   commitment to the tpl remaining unchanged so extension writers need to carry that risk)

Before

After

Created date also present - last modified date is not that useful when geocode jobs or other jobs are updating contacts - what we WOULD find useful is last donation date but I can't make a case for that as a core feature

Technical Details

Comments

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[eileenmcnaughton]

test this please