better flexibility for projects in the suggester configuration

[vladak]

Suggester configuration currently allows to control which projects will have the suggester enabled via the allowedProjects property. It would be nice to be able to express the list of disallowed projects.

Also, it would be nice to be able to express the projecs with patterns (e.g. regular expressions) matched against project name.

This is hand for taming the suggester w.r.t. Java heap usage in the webapp.

[vladak]

Alternatively, make the suggester per-project property.