new port: ncbi-blast+

[cooljeanius (Eric Gallager)]

Besides my comments from #38397 which apply here as well, port -v lint --nitpick also reports the following error:

Error: Port name 'ncbi-blast+' contains unsafe characters. Names should only contain alphanumeric characters, underscores, dashes or dots.

(It's complaining about the "+" symbol)

[sean@…]

Updated, changed + to 'plus' in port name

[ryandesign (Ryan Carsten Schmidt)]

Changing "+" to "plus" is ok. In several other ports we've changed "+" to "x"; you can think about which you like better.

Using ftp://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/LATEST/ for master_sites will fail once this version is no longer the latest version. Let's fetch from ftp://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/${version}/ instead which should be more likely to continue to work in the future.

[sean@…]

Updated name to 'x' convention, changed master_sites to use ${version}