*/R-cran-*: Use cran.mk's default WWW

Remove WWW from my ports because cran.mk provides a default WWW.
See the entry of 20260914 in /usr/ports/CHANGES.

Update R-cran-* WWW to modern URL

Old R-cran-* ports have https://cran.r-project.org/web/packages/${PORTNAME}

New R-cran-* ports have https://cran.r-project.org/package=${PORTNAME}

Replace all the old WWW URLs with new WWW URLs

Reviewed by:	fuz
Differential Revision:	https://reviews.freebsd.org/D59714

devel/R-cran-R.methodsS3: new port

Methods that simplify the setup of S3 generic functions and S3 methods.
Major effort has been made in making definition of methods as simple as
possible with a minimum of maintenance for package developers. For
example, generic functions are created automatically, if missing, and
naming conflict are automatically solved, if possible. The method
setMethodS3() is a good start for those who in the future may want to
migrate to S4. This is a cross-platform package implemented in pure R
that generates standard S3 methods.