Fix generating pmtiles with different file extensions, update XLSForm ordering

[spwoodcock]

Issues

• pmtile generation was currently hardcoded to PNG, ignoring file extension.
• XLSForm ordering not ideal in the field: XLSForm questionaire should come after building validation questions fmtm#1697

Fixes

• Extract the file extension from the tile download, then write the PMTile using specified format.
  • OAM for example downloads by default as .jpg, but it is also possible to add the extension .png to the URL to download PNG format too. It is obviously a much larger file however, and not worth the lossless compression for aerial imagery.
• The digitization verification questions were moved to the end of the XLSForm survey.
  • It's hidden, but could be accidentally deleted by the user if they bulk delete below a certain line. Let's see how it goes.
  • The choices sheet can used a sortby column for sorting, but I don't think such a thing is possible in the survey sheet.
  • If we can manually specify the question sorting, then putting all mandatory fields at the top and hiding would be ideal.

[spwoodcock]

Merging this early to get it in FMTM for the webinar tomorrow.

[spwoodcock]

This was a small refactor, but turned into a bit of a rabbit hole.

Needed to fix the pmtile generation correctly using xy param.
I did a big refactor to improve code readability (imo), which helped me during the debugging process.