[tlbuild] texlive-utah-YYYY mirroring

[Nelson H. F. Beebe]

I have just installed new targets in the /etc/rsyncd.conf file for
rsync://ftp.math.utah.edu/, updated some of the sizes in their
descriptions, and added more internal comments to remind us of what
needs to be updated each year as new TeX Live builds begin.

There are currently 19 rsync targets, of which these apply for TeX
Live:

	% rsync rsync://ftp.math.utah.edu/ | grep ^texlive
	texlive         all of ftp://ftp.math.utah.edu/pub/ctan/tex-archive/systems/texlive [> 6GB]
	texlive-utah    all of ftp://ftp.math.utah.edu/pub/texlive-utah/                    [> 13GB]
	texlive-utah-2016       all of ftp://ftp.math.utah.edu/pub/texlive-utah-2016/       [> 4GB]
	texlive-utah-2017       all of ftp://ftp.math.utah.edu/pub/texlive-utah-2017/       [about 1GB]
	texlive-utah-2018       all of ftp://ftp.math.utah.edu/pub/texlive-utah-2018/       [about 8GB]
	texlive-utah-2019       all of ftp://ftp.math.utah.edu/pub/texlive-utah-2019/       [> 13GB]

The texlive-utah target is an alias for the latest yearly directory,
now texlive-utah-2019, so there is no need to rsync both.  The short
alias is for the convenience of mirror sites that only want the latest
stuff.

The 2018 and 2019 directories contain Images/*.iso files that
contribute to their larger sizes.  Those *.iso files correspond to the
annual DVDs distributed by user groups.

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- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
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