p-confirmDialog should support template

[kapiladiyecha]

[ ] bug report => Search github for a similar issue or PR before submitting
[x] feature request => Please check if request is not on the roadmap already https://github.com/primefaces/primeng/wiki/Roadmap
[ ] support request => Please do not submit support request here, instead see

Current behavior
p-confirmDialog does not have support for ng-template for header/message content, instead of just plain text message and header!

Expected behavior
It should support ng-template, so that user can design whatever way he wants.
Big advantage would be ngx-translate. (Alternative is to translate it from component ts file, but not recommended at all)

• Angular version: 5.2.6

• PrimeNG version: 5.2.3

• Browser: all

• Language: all

[grifin85]

This issue should be open, because didn't create ng-template for message.