AllowEditPost and PostEditTimeLimit migration (#8208)

* AllowEditPost and PostEditTimeLimit migration

* Not set EDIT_POST permission to sysadmin_role if ALLOW_EDIT_POST is configured to NEVER

* Remove a bit of code duplication

model/config.go

@@ -419,7 +419,7 @@ func (s *ServiceSettings) SetDefaults() {
 	}
 
 	if s.PostEditTimeLimit == nil {
-		s.PostEditTimeLimit = NewInt(300)
+		s.PostEditTimeLimit = NewInt(-1)
 	}
 
 	if s.EnablePreviewFeatures == nil {

model/role.go

@@ -182,7 +182,6 @@ func MakeDefaultRoles() map[string]*Role {
 			PERMISSION_UPLOAD_FILE.Id,
 			PERMISSION_GET_PUBLIC_LINK.Id,
 			PERMISSION_CREATE_POST.Id,
-			PERMISSION_EDIT_POST.Id,
 			PERMISSION_USE_SLASH_COMMANDS.Id,
 		},
 		SchemeManaged: true,