feat: tweak stream handling

[wemeetagain]

The ovararching problem with our previous approach is that we're too carefree about managing streams for this protocol.
Specific problems include:

• creating multiple duplicate outbound streams.
• relying solely on a topology to trigger an outbound stream.

Creation and tracking of new streams is tweaked:

• Add an outbound stream queue
  This used to ensure that outbound streams are created sequentially.
  This stops multiple duplicate streams from being created for a single peer.
• Attempt to create an outbound stream when an inbound stream is created.
  This allows us to connect to peers that haven't yet been registered by the topology but want to connect to us.
• Remove PeerStreams usage in favor of managing inbound/outbound streams separately
  PeerStreams works, but obscures some lingering issues. It's also quite inflexible and annoying to modify it since PeerStreams implements an interface in @libp2p/interface-pubsub.

[codecov-commenter]

Codecov Report

Merging #298 (6425378) into master (e1a8586) will increase coverage by 31.90%.
The diff coverage is 91.26%.

@@             Coverage Diff             @@
##           master     #298       +/-   ##
===========================================
+ Coverage   49.58%   81.48%   +31.90%     
===========================================
  Files          43       44        +1     
  Lines        9310     9447      +137     
  Branches      463      917      +454     
===========================================
+ Hits         4616     7698     +3082     
+ Misses       4694     1749     -2945     

Impacted Files	Coverage Δ
src/score/peer-score.ts	87.66% <0.00%> (+33.88%)	⬆️
src/index.ts	70.63% <88.05%> (+8.47%)	⬆️
src/stream.ts	100.00% <100.00%> (ø)
test/2-nodes.spec.ts	99.49% <100.00%> (+67.43%)	⬆️
test/gossip.spec.ts	94.70% <100.00%> (+77.05%)	⬆️
test/signature-policy.spec.ts	99.06% <100.00%> (ø)
test/utils/create-pubsub.ts	78.18% <100.00%> (+3.67%)	⬆️
src/utils/time-cache.ts	91.52% <0.00%> (+1.69%)	⬆️
src/message-cache.ts	79.09% <0.00%> (+5.64%)	⬆️
... and 23 more

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[mpetrunic]

Have you already tried this in lodestar? Any improvements?

[wemeetagain]

Yeah I've linked it against lodestar and it works well.
No more duplicate outbound streams.
No more connections with zero outbound streams.

Also seems like we're getting beacon blocks more on time? I'm seeing a smaller head drift.