Use doc environment if requested

[tlienart]

This is an experimental keyword to support #85

Todo

• check can build Yao
• add docs
• add recommendation / warnings on how to use this best (see use doc environment for servedoc #85 )

[codecov-io]

Codecov Report

Merging #87 into master will decrease coverage by 4.2%.
The diff coverage is 28.57%.

@@            Coverage Diff             @@
##           master      #87      +/-   ##
==========================================
- Coverage   92.34%   88.14%   -4.21%     
==========================================
  Files           4        4              
  Lines         183      194      +11     
==========================================
+ Hits          169      171       +2     
- Misses         14       23       +9

Impacted Files	Coverage Δ
src/LiveServer.jl	100% <ø> (ø)	⬆️
src/utils.jl	73.21% <28.57%> (-13.46%)	⬇️

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