remove check-changelog tool

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

changelog.d/3872.remove

@@ -1 +0,0 @@
-remove BBS/SSH feature, replaced by an external bridge.

changelog.d/3873.fix

@@ -1 +0,0 @@
-UploadedMedia: Add missing disposition_type to Content-Disposition

tools/check-changelog

@@ -1,22 +0,0 @@
-#!/bin/sh
-
-echo "looking for change log of $CI_MERGE_REQUEST_IID"
-
-count=0
-for i in add remove fix security skip; do
-    [ -f changelog.d/"$CI_MERGE_REQUEST_IID"."$i" ]
-    retcode=$?
-    if [ $retcode -eq 0 ]; then
-        echo "found $CI_MERGE_REQUEST_IID.$i"
-        count=$(( count + 1 ))
-    else
-        echo "no $CI_MERGE_REQUEST_IID.$i"
-    fi
-done
-if [ $count -gt 0 ]; then
-    echo "ok"
-    exit 0
-else
-    echo "must have a changelog entry or explicitly skip it"
-    exit 1
-fi