Allow bulk association of project schemes

Currently, if the user would like to associate a project with a certain scheme, they would have to do it manually via the Project administration page. However, if the user wants to edit multiple projects, then they would have to perform it one-by-one.

It would be useful if the user could bulk associate multiple projects with a certain scheme. For example, notification scheme, permission scheme, etc. This would especially help users with a high number of projects, especially when they would like to clear outdated schemes.