Adds a BeforeOp HookType across resolvespec, restheadspec, websocketspec,
mqttspec, and funcspec that fires before every SQL operation (read,
create, update, delete, scan/query) via a new ExecuteBeforeOp helper.
Also closes a row-level-security gap: resolvespec registered a BeforeScan
hook for ApplyRowSecurity but never fired it, and websocketspec/mqttspec
had no BeforeScan hook point at all, so row security was never applied
to their queries. BeforeScan now fires right before the actual scan in
all three, with the (possibly hook-modified) query used for execution.
warkanum
Hein