Make "quote_identifiers" option available on all Db platforms

[hschletz]

The "quote_identifiers" platform option is evaluated only by the Oracle and IbmDb2 platforms. It would be useful with other platforms too because quoting identifiers has the nasty side effect of making them case sensitive. The default behavior of unconditional quoting may cause more problems than it solves for some databases.

[ralphschindler]

Do you want to make a PR for this?

[hschletz]

I'd like to see #7059 integrated first.

[GeeH]

This issue has been closed as part of the bug migration program as outlined here - http://framework.zend.com/blog/2016-04-11-issue-closures.html