fix: size the check icons like the state balls next to them

[markuslf]

The check icons in the host and service lists were rendered at 3em (2em in
minimal lists) while the state ball right next to them measures 2em and 1.5em
respectively. The theme now sizes them to the ball's visible circle, which is
the outer box minus @ball-pad on each side, and shifts them down so both sit
on the same line. The detail header needs its own offset because upstream pulls
the icon up to the row edge there.

The rules carry the .icinga-module.module-icingadb prefix, otherwise they
cannot reach the specificity of the upstream ones: Icinga Web wraps module CSS
in .icinga-module.module-<name>. Both the current (item-layout) and the
pre-1.2 (item-list) class names are covered.

Also adds the missing CHANGELOG.md and bumps the version to 1.1.2.