refactor step1： build spec.Schema; parse object in request

[sdghchj]

Describe the PR
refactor step 1

[codecov-commenter]

Codecov Report

Merging #728 into master will decrease coverage by 0.30%.
The diff coverage is 81.66%.

@@            Coverage Diff             @@
##           master     #728      +/-   ##
==========================================
- Coverage   84.88%   84.58%   -0.31%     
==========================================
  Files           7        7              
  Lines        1872     1790      -82     
==========================================
- Hits         1589     1514      -75     
+ Misses        177      171       -6     
+ Partials      106      105       -1     

Impacted Files	Coverage Δ
gen/gen.go	95.41% <71.42%> (-1.46%)	⬇️
operation.go	87.88% <78.57%> (+0.08%)	⬆️
parser.go	79.76% <85.71%> (-0.66%)	⬇️
schema.go	96.82% <100.00%> (+0.21%)	⬆️

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[easonlin404]

LGTM

[tylfin]

Hmm, I think this broke something, I'm getting:

     {
     "name": "DESCRIPTION",
     "in": "body",
     "schema": {
-        "type": "string"
+        "type": "primitive"
     }

For this param:

// @Param distribution query string false "Name of the distribution to use."

[sdghchj]

@tylfin Got it, fix next PR