iD integration: Use "hashtags" to prefill hashtags and "comment" for a more meaningfull commit message

[tordans]

The current behavior of tasking manager is to prefill the comments section / commit message with hashtags. Those are used by iD to create and prefill the hashtags attributes on the changeset.

This should be change:

• the recommended hashtags should only prefill the hashtags-section in iD
• the comment field should be empty by default and as such suggest a proper message

Alternative solution:
Since the comment field is a required field, I assume it to be an issue to have it empty, since new tasking manager mapper don't know what to do with it.
However, putting the hashtags in there is still not a good solution IMO, it's just clutter.
Instead, maybe add a default text like

Mapping for section https://tasks.hotosm.org/project/5876?task=315

This way there is a link back to the original task where one can see the discussion. And also a more understandable message that does not just show hashtags.

Required change:

• The iD API docs show, that there is the param hashtags that can/should be used https://github.com/openstreetmap/iD/blob/master/API.md.
• This is probably the place for the tasking manager

  tasking-manager/client/app/services/editor.service.js

  Lines 49 to 67 in 39851a1

  	/**
  	* Launch the iD editor
  	* @param centroid
  	* @param changesetComment
  	* @param imageryUrl
  	* @param projectId
  	* @param taskId
  	*/
  	function launchIdEditor(centroid, changesetComment, imageryUrl, projectId, taskId){
  	var base = 'http://www.openstreetmap.org/edit?editor=id&';
  	var zoom = mapService.getOSMMap().getView().getZoom();
  	var url = base + '#map=' +
  	[zoom, centroid[1], centroid[0]].join('/');
  	// Add changeset comment
  	var changeset = ''; // default to empty string
  	if (changesetComment && changesetComment !== ''){
  	changeset = changesetComment;
  	}
  	url += '&comment=' + encodeURIComponent(changeset);

For reference, this is what the URLs look like ATM:
Source

http://www.openstreetmap.org/edit?editor=id&#map=16/-19.97851145722339/33.2391357362335&comment=#hotosm-project-5876 #CycloneIdai #MissingMaps #Mozambique Expanding Road & Waterway Networks&gpx=https://tasks.hotosm.org/api/v1/project/5876/tasks_as_gpx?tasks=87&as_file=false&filename=task.gpx

(Raw format http://www.openstreetmap.org/edit?editor=id&#map=16/-19.97851145722339/33.2391357362335&comment=%23hotosm-project-5876%20%23CycloneIdai%20%23MissingMaps%20%23Mozambique%20Expanding%20Road%20%26%20Waterway%20Networks&gpx=https%3A%2F%2Ftasks.hotosm.org%2Fapi%2Fv1%2Fproject%2F5876%2Ftasks_as_gpx%3Ftasks%3D87%26as_file%3Dfalse%26filename%3Dtask.gpx)

This is also a ping to my list at openstreetmap/iD#5856 (comment)
This is a follow up to openstreetmap/iD#6169 (comment)

[pantierra]

Thanks for the input, @tordans. This is related to #1358.

[pantierra]

Looking into that, I saw on the osm wiki this not being widely agreed on, whether to use hashtags in comments or in the separate field. From a Tasking Manager perspective we add the hashtagged terms into the comment, because it seems most osm tools right now support only to search changesets by comment, not by any tag. Once there is a critical mass of data inspection tools supporting it, it makes a lot of sense to switch or post to both.