Remove server config args that can be read directly from app.

[Tronic]

As discussed in #1796

[codecov]

Codecov Report

Merging #1807 into master will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1807   +/-   ##
=======================================
  Coverage   92.18%   92.18%           
=======================================
  Files          23       23           
  Lines        2315     2315           
  Branches      425      425           
=======================================
  Hits         2134     2134           
  Misses        141      141           
  Partials       40       40           

Impacted Files	Coverage Δ
sanic/app.py	92.25% <ø> (ø)

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