Add optional props for disabling start or end date

[dselmanovic]

We had a use case where the endDate shouldn't have disabled dates since all dates before startDate are disabled by default when the endDate picker is opened. This PR adds an option to enable all dates on both picker sides, start and end.

[codecov]

Codecov Report

Merging #65 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master      #65   +/-   ##
=======================================
  Coverage   99.55%   99.55%           
=======================================
  Files          43       43           
  Lines        1781     1782    +1     
  Branches      518      527    +9     
=======================================
+ Hits         1773     1774    +1     
  Misses          6        6           
  Partials        2        2           

Impacted Files	Coverage Δ
src/RangePicker.tsx	100.00% <100.00%> (ø)
src/hooks/useRangeDisabled.ts	100.00% <100.00%> (ø)

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