Some editorial cleanup

[gmlueck]

• Remove the footer from the HTML build, which contained a confusing date.

• Remove some unused Asciidoc attributes that I think we inherited from another project when we first copied our Asciidoc configuration files.

• Fix some minor bugs in the "syclbase.adoc" file.

I compared the HTML render, and the only change this introduces is due to the first bullet item above. The HTML output no longer contains the line "Last updated" with a confusing date.

[gmlueck]

The error in "Open CTS issue" is unrelated. Merging as editorial