Set default-run to boa removing need for --bin

[RageKnify]

This PR makes it so cargo run runs the boa binary like it used to before boa_tester was introduced.
boa_tester can still be run with cargo run --bin boa_tester.

It changes the following:

-Sets the default run binary to boa

[codecov]

Codecov Report

Merging #837 into master will increase coverage by 0.13%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #837      +/-   ##
==========================================
+ Coverage   59.23%   59.37%   +0.13%     
==========================================
  Files         157      157              
  Lines       10034    10036       +2     
==========================================
+ Hits         5944     5959      +15     
+ Misses       4090     4077      -13     

Impacted Files	Coverage Δ
boa/src/syntax/lexer/cursor.rs	62.71% <0.00%> (+2.02%)	⬆️
boa/src/syntax/ast/node/mod.rs	49.58% <0.00%> (+6.61%)	⬆️
boa/src/syntax/ast/node/new/mod.rs	78.94% <0.00%> (+6.72%)	⬆️
boa/src/syntax/ast/node/identifier/mod.rs	85.71% <0.00%> (+14.28%)	⬆️

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