Add preview/export dialog menu action in the icon browser

[dalthviz]

Creating an issue for a potencial feature idea shown over #300 related with adding a export dialog:

Probably such dialog could be launched from a menu item from the existing icon browser. Also, thinking about it, although exporting the configured icon as .png could be somehow useful, seems to me that something that could be even more useful is to have a way to export the options configured as a dictionary putting them as text in the clipboard for example (something like a Export options button). In that way people could have a way to preview changes to an icon while also being able to get those specific options in a format that they could use in their own code)

[BBC-Esq]

Doh! didn't even realize that you already had a browser style example when I created mine. lol. I'll add the export feature in a separate PR. I'll also look at improving the search functionality the fuzzy searching, but that's be in a separate PR if it turns out to be something worth improving.

[BBC-Esq]

See here #303