Add COPYRIGHT & fix issue with shutterspeed >1sec

[whaan]

One improvement and three bug fixes

Add optional © COPYRIGHT

• move "CUSTOM_TEXT" to top-center (as the title of the photo)
• place COPYRIGHT bottom-right

Use magick instead of convert to be compatible with the latest version of imagemagick

"magick" by itself uses IM v7 syntax. "magick convert" uses the older v6 syntax.
Differences between v6 and v7 syntax are shown on https://www.imagemagick.org/script/porting.php .
V7 syntax is better than v6. It is more powerful, with new features, and has improved error-checking. I suggest that "magick convert" is used only when if you have an old v6 script that doesn't work under v7.
Put it another way: "magick convert" is provided for backwards compatibility. For new work, "magick" should be used.
ImageMagick/ImageMagick#5279 (comment)

Also we now use identify instead of convert -ping

Fix issue with shutterspeeds of longer than 1 sec.

When shutters-eed is more than 1 second, it's not displayed right.
By first checking if it's longer than 1sec, we can print it correctly

Support Camera Models with a space in the name

My camera model is Nikon D7500, but only the first part (Nikon) was printed in the border.
Now we use a separate identify to fetch the cameramodel from the exif which fixes that issue