Draft for bookmarks examples

[stefonarch]

Some ideas for the example file.
I see also why it was hard to use them before: file had to be created by the user first.

To do list:

• save file at first run together with qterminal.ini
• Rework "Find..." button: rename "Load"; open ~/.config/qterminal.org folder; limit to *.xml files
• Message box for backwards compatibility?

[yan12125]

To do list:

Will those improvements part of this PR or other future PRs? If the latter, #886 may be a better place for those notes.

Besides that, this PR looks good. The "Edit bookmarks" one is nice! Although people may not use it often, it provides a good hint.

By the way, a comment like <!-- Some examples to demonstrate how to use bookmarks. Adjust them to fit your needs. --> should make things clearer.

[stefonarch]

I see this as a single PR only related to the the content, #886 is more the "collection" of all ideas, there could come more even,

[yan12125]

Got it! Let's move on!