Creates PurchasesOrchestrator

[vegaro]

We need to separate the public interface from the class itself, so we can reuse the logic in custom entitlements.

To do that, we're going to rename the Purchases class to something private, then create a new Purchases class that only has the public interface. The public interface will redirect all calls and properties to the internal class.

[codecov]

Codecov Report

Merging #1144 (5b91802) into main (32ee171) will decrease coverage by 0.06%.
The diff coverage is 82.95%.

@@            Coverage Diff             @@
##             main    #1144      +/-   ##
==========================================
- Coverage   85.37%   85.32%   -0.06%     
==========================================
  Files         175      176       +1     
  Lines        6194     6261      +67     
  Branches      916      916              
==========================================
+ Hits         5288     5342      +54     
- Misses        560      573      +13     
  Partials      346      346              

Impacted Files	Coverage Δ
.../com/revenuecat/purchases/PurchasesOrchestrator.kt	82.88% <82.88%> (ø)
.../main/kotlin/com/revenuecat/purchases/Purchases.kt	73.04% <83.07%> (-8.25%)	⬇️
...otlin/com/revenuecat/purchases/PurchasesFactory.kt	86.66% <100.00%> (+0.08%)	⬆️

[tonidero]

Love it! nice work!