refactor(bitswap): performance improvements

[gammazero]

• Create fewer copies of wantlist.
• Fewer iterations of wantlist when processing received message.

These changes make some minor improvements and separate these from functional changes in other PR(s).

(lidel) likely closes #625 closes #626

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 59.84%. Comparing base (dfd4a53) to head (b9f9a75).

@@            Coverage Diff             @@
##             main     #634      +/-   ##
==========================================
+ Coverage   59.79%   59.84%   +0.04%     
==========================================
  Files         238      238              
  Lines       29984    29976       -8     
==========================================
+ Hits        17930    17939       +9     
+ Misses      10434    10424      -10     
+ Partials     1620     1613       -7     

Files	Coverage Δ
bitswap/message/message.go	83.87% <100.00%> (+2.86%)	:arrow_up:
bitswap/server/internal/decision/engine.go	90.90% <95.00%> (-0.32%)	:arrow_down:

... and 11 files with indirect coverage changes