The "asym" category is missing from target.json

[joepal1976]

(thanks RJ for pointing this out)

There is an entire section of bundled targets, https://github.com/makehumancommunity/mpfb2/tree/master/src/mpfb/data/targets/asym, which is unreachable since it is not mentioned in https://github.com/makehumancommunity/mpfb2/blob/master/src/mpfb/data/targets/target.json

How this went unnoticed for five years is still to be explained.

Obviously, it should end up among the other bundled targets in the UI.