DOC: Update NOTICE file text

The `NOTICE` file text is not a repetition of the license banner, but clarifications about the licensing of the code (e.g., if in the past had other licenses, or if it derives from pre-exiting code).

Thus, remove the license information and edit the text to reflect the copyright of the code.

Co-authored-by: Oscar Esteban <[email protected]>

NOTICE

@@ -1,15 +1,6 @@
 eddymotion
-Copyright 2021-present The NiPreps Developers <[email protected]>
+Copyright The NiPreps Developers.
 
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may find a copy of the License in the LICENSE file of the
-project root or obtain a copy of the License at
+This product includes software developed by
+the NiPreps Community (https://nipreps.org/).
 
-    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.