Fix communication issues with libp2p (fix of buffer size not recommended/long term solution)

[sa8]

Event handler for messages as they come.

[sa8]

Update: i've added a validator to the pubsub topic.
There are still some issues when scaling. ideally I think that the public commitment of signing and DKG should be posted on the eudico chain to be sure that they are correctly boradcasted (rather than using libp2p broadcast). Will tackle this after submission.

Among other issues (e.g. messages not being delivered correctly to nodes) I also had the following warning:

WARN	pubsub	go-libp2p-pubsub@v0.6.1/tag_tracer.go:157	error bumping delivery tag: unable to bump decaying tag for peer 12D3KooWKEkSex1V8RyM4AQ5Sx75zJeQ5EUUUP6CbaYWEn9PeP87, tag pubsub-deliveries: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, delta 1; queue full (len=128)

I am not sure what this means.