Automatically create store.json file for JsonStore

[synfinatic]

Fixes: #612

[codecov]

Codecov Report

Merging #613 (c719d7e) into main (f178291) will increase coverage by 0.11%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #613      +/-   ##
==========================================
+ Coverage   82.35%   82.46%   +0.11%     
==========================================
  Files          35       35              
  Lines        3241     3244       +3     
==========================================
+ Hits         2669     2675       +6     
+ Misses        502      501       -1     
+ Partials       70       68       -2     

Files	Coverage Δ
internal/storage/json_store.go	92.71% <100.00%> (+3.46%)	⬆️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f178291...c719d7e. Read the comment docs.