feat(services): add onBeforeResizeByContent (onAfter)

[ghiscoding]

• if it takes time to read the entire dataset, we can use these events to show/hide a spinner when the process is over
• another feat is that the onAfterResizeByContent will also return the calculated widths of each column as well and the number of rows that were analyzed

[codecov]

Codecov Report

Merging #335 (3e99fab) into master (fecaaa1) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #335   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          213       213           
  Lines        12992     12999    +7     
  Branches      4282      4282           
=========================================
+ Hits         12992     12999    +7     

Impacted Files	Coverage Δ
...ges/vanilla-bundle/src/services/resizer.service.ts	100.00% <100.00%> (ø)

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