Add count() method to get the count

[naris]

I need to be able to get the count() of rows matching the specification without actually fetching all the rows (for pagination in an Angular/PrimeNG application generated by JHipster).

Could you please add one?

[v-ladynev]

@naris You can extend your repository with standard JpaSpecificationExecutor to use count(specification).
Don't need to extend the library for that.