Added ML Model APIs (load, upload, create metadata). #8

Job	Run time
test-opensearch-spec (version=1.3.17, hub=opensearchproject, tests=default)	1m 25s
test-opensearch-spec (version=2.0.0, hub=opensearchproject, tests=default)	1m 23s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=default)	1m 51s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/index_state_management)	48s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/ml)	6m 7s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=routing)	1m 17s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=snapshot)	58s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=dangling)	52s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/replication)	1m 4s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/streaming)	54s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/notifications)	53s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/query_insights)	48s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/workload-management)	55s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/analysis)	1m 6s
test-opensearch-spec (version=2.18.0, hub=opensearchproject, tests=plugins/security)	45s
test-opensearch-spec (version=2.19.0, hub=opensearchstaging, tests=default)	1m 40s
test-opensearch-spec (version=3.0.0, hub=opensearchstaging, tests=default)	1m 34s
merge-coverage	0s
	24m 20s

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