Make lore lines editable at once (e. g. by importing text input)

[Moepius]

I suggest adding a feature where I can choose to edit more lore lines in a button at once (e. g. with a importing feature), instead of having to add/delete/edit just one at a time.

This would make working with the plugin much quicker, since most of the work that goes into building my GUIs, is copying and pasting the lore lines I prepared in a text editor. Since I can't import/copy buttons (also a feature that would be handy), this is repetitive work, that can be automated.

Making it possible to import .yaml or .txt as input for custom buttons, would make it easier for people who have huge GUIs with many subpages and a bunch of lore lines for each button.

The file could look sth. like this

my_custom_button:
button_name: &3&l[cool name]
button_material: barrrier
button_lore:

• line 1
• line 2
• line3

my_custom_button2:
...

[Greazi-Times]

This could be made in corporation with #38