q2-composition - removed vega* from source tree

[Steffen Möller <steffen_moeller@gmx.de>]

Hello,

I am tempted to upload the package as it is. It is apparently version 4
of Vega that is expected, not version 5 that just entered the archive
(many, many thanks!!) and they are apparently using
https://github.com/vega/vega-embed which we yet do not have. However, 
those embedded vega files will affect the presentation of the results
but not the results themselves and as such this package is already
useful. I propose to craft a bug report early about the package to
prevent its migration to testing and talk to upstream about.

https://salsa.debian.org/med-team/q2-composition

What do you think?

Best,
Steffen