[Feature Request] Save signature images for future use

[PancakeZik]

It would be handy to be able to save images of signatures so you don't have to reuploaded them each time you are signing something.

Thanks!

[Royal2000H]

Seems version 0.31.0 introduced support for pre-saved files stored at /customFiles/signatures/.

Now we just need the ability to save a drawn signature into there.

[Frooodle]

There are three features as part of this -1 Export saved signature to png

-2 Export signature into customFiles/signatures/ Due to the ability to misuse this and fill up server with pre-saved images, I would want this to be disabled via default

-3 option to save to cache/local-storage should be done Save to device / Save to server

[ZeGuigui]

To be able to save signatures either ton customFiles/signatures or browser local storage would be perfect. I will try adding my compagny logo inside the ALL_USERS folder