[META] Document changes related to the OpenSearch Software Foundation

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What/Why

What are you proposing?

The Linux Foundation announced the launch of the OpenSearch Software Foundation here.

Document the various community aspects/processes/content related to new OpenSearch Software Foundation.

• [FEATURE] Document the OpenSearch Software Foundation governing board (GB) #49
• [FEATURE] Document formation of the Technical Steering Committee (TSC) #48

Documenting and transferring infrastructure is opensearch-project/.github#220.

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In #51 I updated the copyrights.