Select BLAST+ 2.2.26 binaries via uname/arch specific actions.

Based on a sample configuration file from Dave Bouvier which he
had used in testing the new <actions> enhancements and shared
as documentation.

This was modified to use $INSTALL_DIR instead of $INSTALL_DIR/bin
and the (unreliable) compilation fall back replaced with logging
requesting the user file their uname/arch combination on GitHub.

The old system using shell scripting was fragile with the system
shell (e.g. bash vs sh).