Insights/api frozen insights

Created by: coury-clark

Adds DB migration and basic GQL response for isFrozen field.

Test plan

Tested locally - see below

query insightview{
  insightViews (id:"aW5zaWdodF92aWV3OiIyNVU3alhuVWNUbjZZaWNkZ01MZXN1Q0F1ZmUi") {
    nodes {
      id
      isFrozen
      appliedFilters {
        excludeRepoRegex
        includeRepoRegex
      }
      defaultFilters {
        excludeRepoRegex
        includeRepoRegex
      }
      dataSeriesDefinitions {
        ... on SearchInsightDataSeriesDefinition {
          query
        }
      }
    }
  }
}

{
  "data": {
    "insightViews": {
      "nodes": [
        {
          "id": "aW5zaWdodF92aWV3OiIyNVU3alhuVWNUbjZZaWNkZ01MZXN1Q0F1ZmUi",
          "isFrozen": false,
          "appliedFilters": {
            "excludeRepoRegex": null,
            "includeRepoRegex": null
          },
          "defaultFilters": {
            "excludeRepoRegex": null,
            "includeRepoRegex": null
          },
          "dataSeriesDefinitions": [
            {
              "query": "func"
            }
          ]
        }
      ]
    }
  }
}