Improvement/import tool progress indication

[johnnyaug]

Closes #798

[codecov-io]

Codecov Report

Merging #804 into master will increase coverage by 0.01%.
The diff coverage is 60.00%.

@@            Coverage Diff             @@
##           master     #804      +/-   ##
==========================================
+ Coverage   41.88%   41.89%   +0.01%     
==========================================
  Files         133      133              
  Lines       10422    10435      +13     
==========================================
+ Hits         4365     4372       +7     
- Misses       5477     5482       +5     
- Partials      580      581       +1     

Impacted Files	Coverage Δ
onboard/import.go	62.74% <0.00%> (-2.57%)	⬇️
onboard/catalog_actions.go	67.85% <45.45%> (-2.28%)	⬇️
block/s3/inventory_iterator.go	85.50% <100.00%> (+0.89%)	⬆️

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[nopcoder]

Think that it will be better to have these as int64 and when we call the atomic increment get the address of the variable - so we will not be required to handle nil.

[nopcoder]

related to the previous talk about this code -

The doc about why you need to use atomic load when you use atomic API - https://preshing.com/20130618/atomic-vs-non-atomic-operations/

[nopcoder]

Cool