x11-wm/herbstluftwm update to 0.8.0

Port changelog:

• use cmake build system
• added textproc/asciidoc build depend
• use xrandr
• remove shell completions option as Porter's Handbook suggests

Program changelog (https://herbstluftwm.org/news.html):

• single window floating (every client has an attribute floating which

	  can be set at run time and via the rule consequence floating=on)

• monitor detection via xrandr
• detection of external panels
• new commands: apply_rules, drag, export
• new client attribute: keys_inactive (negation of keymask)
• some minor improvements and bug fixes

PR: 245527
Submitted by: Zsolt Udvari <uzsolt@uzsolt.hu> (maintainer)