Release v1.0.0.0-beta1

Compatible with OpenSearch 1.0.0

Enhancements

• migrate plugin to be compatible with OpenSearch #1
• rename plugin #5

Infrastructure

• update github workflows #5

Documentation

• update NOTICE, README, LICENSE, CONTRIBUTING files; add MAINTAINERS file; update issue and PR template files #1
• add SPDX license header for gradle files #2
• add SPDX license header to all files #3
• update MAINTAINERS file #5
• add release notes for 1.0.0.0-beta1 release #6