[YUNIKORN-789] Add NOTICE and DISCLAIMER files to all yunikorn repos (#53)

Add NOTICE and DISCLAIMER files
diff --git a/DISCLAIMER b/DISCLAIMER
new file mode 100644
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--- /dev/null
+++ b/DISCLAIMER
@@ -0,0 +1,8 @@
+Apache YuniKorn (Incubating) is an effort undergoing incubation
+at The Apache Software Foundation (ASF), sponsored by the Apache Incubator.
+Incubation is required of all newly accepted projects until a further review
+indicates that the infrastructure, communications, and decision making process
+have stabilized in a manner consistent with other successful ASF projects.
+While incubation status is not necessarily a reflection of the completeness
+or stability of the code, it does indicate that the project has yet to be
+fully endorsed by the ASF.
diff --git a/NOTICE b/NOTICE
new file mode 100644
index 0000000..94d7938
--- /dev/null
+++ b/NOTICE
@@ -0,0 +1,5 @@
+Apache YuniKorn (Incubating)
+Copyright 2019-2021 The Apache Software Foundation
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).