More central configuration enablement

[axw]

Enable central configuration for:

• stack_frames_min_duration
• stack_trace_limit

Closes #741

[codecov-io]

Codecov Report

Merging #742 into master will increase coverage by 0.08%.
The diff coverage is 79.45%.

@@            Coverage Diff             @@
##           master     #742      +/-   ##
==========================================
+ Coverage   84.59%   84.68%   +0.08%     
==========================================
  Files         127      127              
  Lines        8271     8350      +79     
==========================================
+ Hits         6997     7071      +74     
- Misses        892      894       +2     
- Partials      382      385       +3     

Impacted Files	Coverage Δ
module/apmecho/middleware.go	88.77% <0.00%> (ø)
module/apmechov4/middleware.go	88.77% <0.00%> (ø)
module/apmgin/middleware.go	86.84% <0.00%> (ø)
module/apmhttprouter/handler.go	76.19% <0.00%> (ø)
module/apmrestful/filter.go	90.00% <0.00%> (ø)
profiling.go	71.87% <0.00%> (-3.54%)	⬇️
module/apmzap/core.go	64.10% <50.00%> (ø)
config.go	76.63% <62.50%> (-0.25%)	⬇️
tracer.go	88.85% <84.21%> (+1.49%)	⬆️
error.go	95.09% <100.00%> (+0.13%)	⬆️
... and 7 more

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