Implemented simple quote provider for ING

[oxisto]

Can be useful for derivates.

Fixes #165

[codecov]

Codecov Report

Merging #166 (a459d1b) into main (01afb56) will decrease coverage by 0.16%.
Report is 1 commits behind head on main.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##             main     #166      +/-   ##
==========================================
- Coverage   86.22%   86.07%   -0.16%     
==========================================
  Files          19       20       +1     
  Lines         900      919      +19     
==========================================
+ Hits          776      791      +15     
- Misses         87       89       +2     
- Partials       37       39       +2     

Flag	Coverage Δ
unittests	86.07% <80.00%> (-0.16%)	⬇️

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

Files	Coverage Δ
service/securities/quote_provider.go	100.00% <100.00%> (ø)
import/csv/csv_importer.go	96.00% <50.00%> (-1.94%)	⬇️
service/securities/quote_provider_ing.go	86.66% <86.66%> (ø)