Bug 33236: Move NewSuggestion to Koha::Suggestion->store

Bug 33236: Move NewSuggestion to Koha::Suggestion->store

The NewSuggestion routine saved the suggestion to the DB
and returned the id

This patch moves the code to Koha::Suggestion->store and
handles emailing upon creation, this adds that functionality to
suggestions added via api

To test:
1 - Apply patch
2 - Test adding a suggestion on the opac and staff client
3 - Confirm the suggestions are added correctly

Signed-off-by: Andrew Auld <andrew.auld@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>