Specify time offset for a camera that did not geotag

[bhousel]

If a camera did not geotag its images for some reason, we can interpolate geotags from the other cameras that did.

I wrote some hacky code that sort of did this in an automatic way:

            // Missing gps coordinates.
            // Try to grab coordinates from another camera at same time.
            if (!Array.isArray(coord) || coord.length < 2) {
                for (let k = 0; k < cameras.length; k++) {
                    if (k === i) continue;
                    let cameraAlt = cameras[k];
                    let fileAlt = alltimes[time][cameraAlt];
                    if (!fileAlt) continue;

                    let dataAlt = extractExif(allfiles[fileAlt].data);
                    let coordAlt = dataAlt.coord;
                    if (!Array.isArray(coordAlt) || coordAlt.length < 2) {
                        continue;
                    }

                    // offset slightly so they don't appear coincident
                    coord = coordAlt.map(c => c + 0.000001);
                    break;
                }
            }

But it doesn't really work because the misbehaving camera isn't necessarily timestamping in sync with the gps camera. It might be off by seconds. So we need to flag this as a warning and run a different command to fix the geotags after a reviewer supplies the offset.