udevadm-hwdb: use common verb help and add --introspect-cli

The custom help() is replaced by the common verb help, which derives the
synopsis, abstract, and option list from the verb declaration in udevadm.c
and the "udevadm-control" option namespace. The new VERB_DEPRECATED flag
is used.

test/units/TEST-74-AUX-UTILS.introspect-cli.sh

@@ -214,6 +214,10 @@ udevadm --introspect-cli | jq -e \
     '.commands[] | select(.names[0] == "udevadm") | .verbs[] | select(.names[0] == "info") |
         [.options[].names[-1]] | contains(["--query", "--json", "--no-pager"])'
 
+udevadm --introspect-cli | jq -e \
+    '.commands[] | select(.names[0] == "udevadm") | .verbs[] |
+        select(.names[0] == "hwdb") | .isDeprecated == true'
+
 # systemd is optionally a multicall binary that also provides systemd-executor
 if [[ "$(readlink "$(command -v systemd-executor)" 2>/dev/null)" == systemd ]]; then
     systemd --introspect-cli | jq -e \