Add Advanced feature to allow Form scripts

Summary Add scripting support for advanced users to supply scripts that allow them to control forms and fields with access to stores, apis etc. These scripts can be served by the Directus api using a /script endpoint. This allows app extensibility to a whole new level. There are times when you want to be able to control how fields behave, how they are displayed, filtered based on rules that can't be done with "conditions" configuration or calculations between fields on input. The idea is to have freedom of control over the entire form as a whole as a Vue engineer or just a js programmer. Below is an example of scripts added to a "Quotas" collection. I added this to the end of the directus collections model configuration and allows the following configuration: , just othe…