Add PhotoSwipe demo gallery

[azett]

Good idea by @Fraenkiman: A freshly-installed FP should have a small PhotoSwipe demo gallery in the Welcome entry.

[Fraenkiman]

hello @azett what do you think of this variant?

You can ignore the emoticons. ...whereby a few yellow grimaces make the welcome page look different. What do you mean? After all, the first impression decides whether a potential user decides to use FlatPress permanently or not.

However, the condition must be met that the images + .captions.conf are already in the /fp-content/images/Leggero-Themepreview directory before running the setup or are copied there during the setup.

Best regards Frank

[Fraenkiman]

hello @azett,

It may be possible to include the content negotiation from #198 in default.php and settings-defaults.php as the default language.

Then the user gets the welcome entry displayed in the appropriate language.

Best regards Frank