Add download link to be able to view attachement in a popup or downlo…

[JLTRY]

Left icon is for viewing attahcment . Right one is for download (if secure download options is set)

[parapente]

@JLTRY testing this patch I noticed that if you don't select to open the file in a modal the file url is exposed to the user. Secure download and modal should work as is (you just have to select from the attachments options -> Security to download the file inline).

If what you want to achieve is to have the file both show in a modal and have an icon to download then you should keep the url as is and just show the extra icon whenever the option to open the attachment in a modal is enabled. It would be nice to be configurable too.

[JLTRY]

@parapente I rewrote feature
It will show only in popup mode + if option is selected

[parapente]

Please don't merge this yet. I need to push a couple of changes. Looks good now.

[parapente]

@JLTRY see the suggestions above and the changes I made and if you agree merge the PR.