RFC: Triggers at Business Logic Layer

The idea is to have triggers that run at business logic layer before or after data is inserted, updated or deleted into a table. This will allow for custom business logic without changes to schema. This logic will apply whether data is inserted directly into the table or via nested mutation.

[Salesforce Triggers](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_triggers.htm) is a similar concept which is very powerful. Salesforce Triggers also support [Transactions](https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_transaction.htm) at the business logic layer. Notably, in Salesforce triggers, data is processed in batches of usually 200 records.

e.g. Consider a Customer table with an array relationship to Address table, and there is a custom logic for validating addresses. Use cases are that Address validation should run when inserting directly into Address, and when doing a nested insert into Account as well as Address. A business logic trigger that runs before Insert and before Update will work well. With Actions, two custom Actions will need to be created, adding to the schema as well as creating duplicate code.