Added survey:date when adding mapillary image tag

[thibaultmol]

It might be useful to add a survey:date value to an object when you click the "Add Mapillary tag" button.
Piv4review also does this, when you add the mapillary imagery, it adds a survey date with the date of when the photo was taken.
(it shouldn't overwrite a newer date obviously, but it should overwrite older dates)

[taylor.smock]

Looking at ​osmwiki:Key:survey:date,

The key survey:date=* can be used to indicate the date when a node, way or relation was last surveyed or verified in person.

​osmwiki:Key:check_date might be a better fit.

If you think that ​osmwiki:Key:survey:date is better, you may want to kick off a conversation over whether or not it should also apply to images taken of the object(s) in question on a specified date (I think so, but the wiki is specifically talking about "in person")

Anyway, I'm on the fence about this -- I'll have to check and see what StreetComplete looks at and updates. I'd also prefer to only add it to objects that have been completely reverified on that date, if I don't do subtags (which I probably won't -- I don't know what the workflow is for most people who use it. Do they add the tag, then the information, or vice versa? One I can detect and pick subtags, the other I cannot).

Thank you for your enhancement request. I'll have to think about it.

[taylor.smock]

@thibaultmol:

Thank you for your feature request. Unfortunately, I don't have a good way to figure out what the user looked at (did they verify all the tags?), so I cannot add the check_data/survey_date tags. If I could tell what bits were pulled from the picture, I could add check_date:<tag>, but that dramatically increases the number of tags in the database.

I know this isn't exactly what you wanted, but I don't want to add a tag that may be semantically wrong (both of the possible tags are supposed to be used when the user checks all the tags on the object), and I don't want to try and guess what tags are from the image and what are from other sources (like aerial).