Quotation Marks in INI-files

Hi everyone and first of all: thanks for the amazing work.

The issue I'm having is like that in #760, but this time with regard to INI-files. When I encrypt a string that is enclosed in quotation marks, the quotation marks are gone after decryption. This makes a difference regarding PHP's parse_ini_*-functions, which will accept, e.g., exclamation marks only within quotation marks. Since there apparently is no real INI-standard, they also are well within their rights to handle it like that, apparently.

While the problem can be mitigated by adjusting the scanner mode the functions use, this is not an attractive solution if the call to the function is buried somewhere inside of framework code. It seems to me that it would be best if sops reproduced the entered text verbatim, if that should be an option.

The issue names no repository files or tests; start by reproducing the reported loss of quotation marks when encrypting and decrypting an INI value. Check how an optional verbatim-preservation behavior would interact with PHP parse_ini_* functions, and consider the work done when quoted input can be preserved without breaking existing INI handling.