docs: plugins, cloudflare, sdk, elements, database (#240)

* docs: added plugins docs, updated cloudflare docs

* updated cli help text

* added `systemEntity` and added docs on how to work with system entities

* docs: added defaults to cloudflare image plugin

* docs: updated sdk and elements

app/src/auth/AppAuth.ts

@@ -14,6 +14,7 @@ import { usersFields } from "./auth-entities";
 import { Authenticator } from "./authenticate/Authenticator";
 import { Role } from "./authorize/Role";
 
+export type UsersFields = typeof AppAuth.usersFields;
 export type UserFieldSchema = FieldSchema<typeof AppAuth.usersFields>;
 declare module "bknd" {
    interface Users extends AppEntity, UserFieldSchema {}