build - Apply spotless license header checks to shell scripts (#7048)

* build - apply license to shell scripts
* build - shell script license text
* fix - Add missing shebang line in evmtool benchmark shell scripts
* build - update shell license text and spotless regexp
* build - apply license header to shell scripts
* fix - Update shebang in splitList to use bash

---------

Signed-off-by: Usman Saleem <usman@usmans.info>

scripts/dco_check.sh

@@ -1,4 +1,18 @@
 #!/bin/bash
+##
+## Copyright contributors to Hyperledger Besu.
+##
+## Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+## the License. You may obtain a copy of the License at
+##
+## http://www.apache.org/licenses/LICENSE-2.0
+##
+## Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+## an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+## specific language governing permissions and limitations under the License.
+##
+## SPDX-License-Identifier: Apache-2.0
+##
 
 status=0
 while IFS= read -r -a line; do