Andymck/use peerbook in libp2p

[andymck]

Includes changes required to incorporate the standalone peerbook into erlang-libp2p
Associated erlang-libp2p PR: helium/erlang-libp2p#265

[codecov]

Codecov Report

Merging #2 into master will decrease coverage by 13.32%.
The diff coverage is 37.80%.

@@             Coverage Diff             @@
##           master       #2       +/-   ##
===========================================
- Coverage   89.47%   76.14%   -13.33%     
===========================================
  Files           2        2               
  Lines         285      348       +63     
===========================================
+ Hits          255      265       +10     
- Misses         30       83       +53     

Impacted Files	Coverage Δ
src/libp2p_peerbook.erl	63.59% <32.30%> (-17.82%)	⬇️
src/libp2p_peer.erl	94.36% <58.82%> (-4.86%)	⬇️

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