Element Desktop removes additional properties in the sticker info, but
not the media info. Element Android removes them in both currently. This
commit moves the net.maunium.telegram.sticker property to the media
info. This can be combined with a change to mautrix-telegram that
bridges telegram-imported matrix stickers to matrix stickers.
The license was initially MPLv2 as I expected the project to be a fairly
simple tiny web app, but it has already grown into multiple files. Now
that I'm going to add a server component, I'm switching the license for
future versions to AGPL like all my other non-library projects.
The image quality shouldn't be reduced, but it should be shown smaller in clients.
Also add compatibility hack for broken clients like Element iOS that require a thumbnail_url