[AC-1708] Teams Starter Plan (#3386)

* Upgraded old 2019 plans to have the same features as 2020 and beyond

* Removed redundant test and moved additional test cases to GetByOrgIdAsync_SmNoneFreePlans_ReturnsNull

* Fixed issue where feature flag wasn't returning correct plans

* Added teams 2010 plan

* Reverted accidental change to StripePaymentService

* Split feature flag logic and added some explanatory comments

* Removed families changes

* Resolved issue where Teams Starter could not sign up for a new org with SM enabled

* Fixed issue with signing up for SM with Teams Starter

* Resolved issue where an active plan could increase their SM seat count to be greater than the base seats in the password manager plan

* Updated unit test to ensure Seats are higher than SmSeats

* Resolved issue where getting plans would return a value that LINQ previously cached when feature flag was in a different state

src/Core/Enums/PlanType.cs

@@ -36,4 +36,6 @@ public enum PlanType : byte
     EnterpriseMonthly = 14,
     [Display(Name = "Enterprise (Annually)")]
     EnterpriseAnnually = 15,
+    [Display(Name = "Teams Starter")]
+    TeamsStarter = 16,
 }

src/Core/Enums/ProductType.cs

@@ -12,5 +12,7 @@ public enum ProductType : byte
     Teams = 2,
     [Display(Name = "Enterprise")]
     Enterprise = 3,
+    [Display(Name = "Teams Starter")]
+    TeamsStarter = 4,
 }