[chore] Admin CLI + new account creation refactoring (#2008)

* set maxPasswordLength to 72 bytes, rename validate function

* refactor NewSignup

* refactor admin account CLI commands

* refactor oidc create user

* refactor processor create

* tweak password change, check old != new password

internal/gtsmodel/admin.go

@@ -17,7 +17,10 @@
 
 package gtsmodel
 
-import "time"
+import (
+	"net"
+	"time"
+)
 
 // AdminAccountAction models an action taken by an instance administrator on an account.
 type AdminAccountAction struct {
@@ -45,3 +48,23 @@ const (
 	// AdminActionSuspend -- the account or application etc has been deleted.
 	AdminActionSuspend AdminActionType = "suspend"
 )
+
+// NewSignup models parameters for the creation
+// of a new user + account on this instance.
+//
+// Aside from username, email, and password, it is
+// fine to use zero values on fields of this struct.
+type NewSignup struct {
+	Username string // Username of the new account.
+	Email    string // Email address of the user.
+	Password string // Plaintext (not yet hashed) password for the user.
+
+	Reason        string // Reason given by the user when submitting a sign up request (optional).
+	PreApproved   bool   // Mark the new user/account as preapproved (optional)
+	SignUpIP      net.IP // IP address from which the sign up request occurred (optional).
+	Locale        string // Locale code for the new account/user (optional).
+	AppID         string // ID of the application used to create this account (optional).
+	EmailVerified bool   // Mark submitted email address as already verified (optional).
+	ExternalID    string // ID of this user in external OIDC system (optional).
+	Admin         bool   // Mark new user as an admin user (optional).
+}