chore(server): add position, bgColor & title to story & page json respectively for published story

[pyshx]

Overview

This PR adds support for panelPosition ,bgColor and title fields in storyJSON and pageJSON respectively to have access to them in published stories.

[netlify]

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Name	Link
🔨 Latest commit	a49c3da
🔍 Latest deploy log	https://app.netlify.com/sites/reearth-web/deploys/6548e9c6cda84c000811445e

[codecov]

Codecov Report

Merging #787 (a49c3da) into main (c158b69) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #787      +/-   ##
==========================================
- Coverage   25.97%   25.97%   -0.01%     
==========================================
  Files        1630     1630              
  Lines      178057   178060       +3     
  Branches     3913     3913              
==========================================
  Hits        46247    46247              
- Misses     130721   130724       +3     
  Partials     1089     1089              

Flag	Coverage Δ
server	33.36% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
server/pkg/scene/builder/story.go	0.00% <0.00%> (ø)
server/pkg/storytelling/story.go	59.32% <0.00%> (-1.03%)	⬇️