Create Payment Plans

[igorsimb]

• [x] Create names of the plan.

Example: https://priceva.ru/subscription

• [x] Create exact price and quotas for each plan.

• [x] Create a model for the plans

It should be a class within Tenant class (similar to Status). E.g.

class PaymentPlan(models.Model):
    name = models.CharField(max_length=100)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    duration = models.IntegerField(help_text="Duration in days")

Other names for the class:

• SubscriptionPlan

• MembershipLevel

• PricingTier

• SubscriptionPackage

• PlanOption

• [ ] https://github.com/igorsimb/mp-monitor/issues/152