532 bookmark no long press

[BPerlakiH]

Fixes #532 additional feature change:

Adding the option to add and remove bookmarks without long-press gesture as well, by adding the bookmark icon to the opened sheet top right menu item. It can have 3 states:

• disabled if no url is loaded
• enabled, but off - when the url is not bookmarked
• enabled and on - when the url is bookmarked already

[BPerlakiH]

Is the bookmark icon in toolbar changing state based on whether current page is already bookmarked?

Yes it is updating dynamically.

[kelson42]

@BPerlakiH Please rebase and fix conflicts

[BPerlakiH]

@kelson42 I've rebased it