Rework vendored dependencies

First upload of usql was rejected by FTP Master:

Hi,

your debian/copyright entry for debian/vendor/github.com/kenshaw/rasterm/* does not seem to be complete.

If your debian.tar is almost half the size of your orig.tar, something went wrong. Please remove at least all packages that are not in Debian from your debian/vendor. No, github.com/xo/tblfmt is not just a tiny package.

This new versiona addressess all issues. See commits for details.

This depends on multiple dependencies to land in Debian first:

• golang-github-xo-dburl!1 (merged)
• golang-github-xo-tblfmt!1 (merged)
• golang-github-gohxs-readline!3
• golang-github-mattn-go-sixel!1 (merged)
• golang-github-ziutek-telnet!1 (merged)
• golang-github-google-goexpect!1 (merged)