feat(core): add loading spinner to AutoComplete Editor/Filter

[ghiscoding]

• add SASS styling to use the jQuery UI loading styling (internally jQuery UI will automatically add the CSS class "ui-autocomplete-loading" whenever processing) which shows up after few milliseconds (when using remote calls)

[codecov]

Codecov Report

Merging #65 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #65   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          193       193           
  Lines        10209     10213    +4     
  Branches      3423      3423           
=========================================
+ Hits         10209     10213    +4     

Impacted Files	Coverage Δ
packages/common/src/editors/autoCompleteEditor.ts	100.00% <100.00%> (ø)
packages/common/src/filters/autoCompleteFilter.ts	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3156cc5...d591de7. Read the comment docs.