MacOS dock: rename wallet with official name

[Thykof]

          @longgamma-massa question about the product: it's "Massa Wallet" in the store. I think it should be same in the dock:

Originally posted by @Thykof in #423 (comment)

[thomas-senechal]

AFAIK, the name displayed in the dock is based on the name of the .app.
As we store the plugin as wallet-plugin.app, it shows wallet-plugin.

Maybe there are ways to override it, or maybe we can simply rename it. But I don't know what renaming the .app implies for MS (do we need the name to be the same as the directory? do we just use the first .app we find ?...)