more metadata for the arms images

[kmexter]

Now that the image filenames and URLs are accessible from the plutof download as harvested into github (associated_data_[observatory], the information therein needs to be supplimented
In particular we would like

• the plate number and side (and if there are >1image for a plate and side, that is OK, maybe add an iterator tho)
• if this is a field image instead

To check out how possible this is to do on the current crop of images

• are the filenames presented well enough to get this info from there?
• are enuf events provided with an image-explanation spreadsheet, well enough formatted, that this can be used
• perhaps may need to do some manual work, e.g. indicating where to use the filename, where to use a CSV file, and perhaps even myself editing those CSV files where they are not quite right
• what other metadata from the images pages on plutof do we want to add to this spreadsheet, so they can be made visible (as the metadata page on plutof for each image is not downloadable from outside, only the actual image is). is there more metadata there than is in the .jpg images themselves anyway?

If yes to the above, then @kmexter should go ahead and do the necessary preparation and the @cedricdcc will write the script to impliment these actions

[kmexter]

We have added a bit of code that extracts plate number and face to the metadata, when those info are available. Waiting for user feedback on whether more is wanted