20197 Dashboards: report the reason a visualization is unavailable

The widget wizard greyed out visualization types that do not fit the
configured data selection, but the tooltip always blamed the Checkmk
edition. The disabled-tile tooltip now takes its text from whichever
check disabled the tile, so it names the data selection where that is
the blocker and the edition only where it really applies.

JIRA-Ref: SUP-29466
Change-Id: I8e34fd86d7bc0d97461f3bcfee4da3fc171e70b1