Integrate ElasticSearch and include component template for the “power saving status table”

[PrathibaJee]

• Integrate Elasticsearch service from onf-core-model-ap/applicationPattern/services/ElasticsearchService
• Include Elasticsearch preparation during the startup of the application to point to the expected index-alias as specified in the LAYER_PROTOCOL_NAME_TYPE_ELASTICSEARCH_LAYER instance,

ElasticSearch preparation shall include the following functionality ,

• Configuration of index template. If a index is not available , create an index as per the alias mentioned in the config file.
• Include a component template for the “power saving status table” for saving the deviation-from-original-state modules-to-restore-original-state information & with the following entry ,

{
        name: 'aips-pss-mappings',
        body: {
            template: {
                mappings: {
                    properties: {
                        'link-id': { type: 'keyword' },
                        'deviation-from-original-state-list': { type: text }, // should not be type: 'flattened'as the list is not an object
                        'modules-to-restore-original-state-list': { type: text } // should not be type: 'flattened' as the list is not an object
                    }
                }
            }
        }
    } 

As per the expectation , 'deviation-from-original-state-list’ and ‘modules-to-restore-original-state-list’ shall be a list.
In Elasticsearch, there is no dedicated array data type. Any field can contain zero or more values by default, however, all values in the array must be of the same data type.
Reference : https://www.elastic.co/guide/en/elasticsearch/reference/current/array.html
So , defining the datatype of deviation-from-original-state and modules-to-restore-original-state of type text shall be fine.

A final entry shall be like this ,

"_source" : {
          "link-id" : "305551239",
          "deviation-from-original-state-list" : [ ],
          "module-to-restore-original-state-list" : [
            "AllTransmittersOn"
          ]
        }

[IswaryaaS]

Included changes as part of #94.

Would test once and close the issue

[vanithavalluripalli9]

Fixed as part of PR #94. Tested and verified