fix: Added Registrar, Dialer and Connection Manager to Libp2p object

[maschad]

Closes #338

[achingbrain]

This is intentional to reduce the size of the libp2p api and to encourage people to use the high level methods on the libp2p node instead of reaching into the low-level components (e.g. use libp2p.dial instead of libp2p.connectionManager.openConnection etc).

[maschad]

This is intentional to reduce the size of the libp2p api and to encourage people to use the high level methods on the libp2p node instead of reaching into the low-level components (e.g. use libp2p.dial instead of libp2p.connectionManager.openConnection etc).

I understand the intention to reduce the size of the libp2p api but given that the ConnectionManager and Registrar are core to the library it would seem that those interfaces should be extended.

The impetus for this PR arose out of instances like this where more often that not a Libp2p instance would require being initiated with a ConnectionManager and Registrar (in this case for Gossipsub).

Are there multiple instances where a consumer would not want to utilize the default connection manager?
(This relates to the broader suggestion posed here)

[p-shahi]

Closing per discussion in triage meeting for reasons mentioned here: #339 (review)

Looking into alternative options where one can optionally pass in their own connection manager module