added opening_hours="by appointment"

[soham-dixit]

Fix #653

Added "by appointment" option for opening hours editing.

Screenshots:

[Zverik]

This is a good idea, thank you Soham for taking this on. There are two things to improve:

1. The "by appointment" is a single case of "commented" opening hours. Other comments could be put in there too, so maybe it might mandate a couple buttons in this panel, like "by appointment" and something else (need to check with taginfo), and a custom comment field?
2. There need to be weekdays for the appointment field. I often encounter normal working hours on Mo-Fr, but "Saturdays - by appointment".
3. Generally why I postponed adding comments is, comments can be attached to any of the blocks. And there can be even intersecting opening blocks with different comments, e.g. "legal persons" and "general" for banks. But this seems to be too hard of course. But generally, it might be better to have a "by appointment" button for all panels, that also allows not to choose time intervals. But again, this might be too hard and better be postponed.

I'd suggest doing 2 and maybe custom field from 1 for this pull request.

[soham-dixit]

Thanks for the feedback @Zverik!

1. The "by appointment" is a single case of "commented" opening hours. Other comments could be put in there too, so maybe it might mandate a couple buttons in this panel, like "by appointment" and something else (need to check with taginfo), and a custom comment field?

Regarding above point, I checked OSM taginfo, and noticed that the value "closed" actually appears more frequently than "by appointment" under opening_hours. Do you think it would make sense to add a dedicated button for "closed" as well, along with "by appointment"?

Also, just to clarify about the custom comment field:

• Should the input be stored as opening_hours="user's custom comment"?
• Or do we need to introduce a separate key like comment="..."?

2. There need to be weekdays for the appointment field. I often encounter normal working hours on Mo-Fr, but "Saturdays - by appointment".

Makes sense, though are you suggesting that the format should support something like Mo-Fr 09:00-17:00; Sa by appointment? Or expecting something different in implementation?