Instance - support keyword search by classifications field

Purpose/Overview:
The purpose of this story is to allow the user a keyword search within classifications field only.

Requirements/Scope:
1. Case insensitive
2. Word match in the following Inventory Instance field: classifications[].classificationNumber

Acceptance criteria:

• Query returns accurate hit count
• User can search by any word that is a part of the field's value
• Results are ranked based on term frequency, inverse document frequency and field length
• Stemming according with configured on the tenant language tokenizers

Outside the scope

• UI work
• AND, OR, NOT and NESTING

Additional Information:
Examples of classification values:

"classifications": [
    {
      "classificationNumber": "HJ2154.3 .S28 2013eb",
      "classificationTypeId": "ce176ace-a53e-4b4d-aa89-725ed7b2edac"
    },
    {
      "classificationNumber": "336.567",
      "classificationTypeId": "42471af9-7d25-4f3a-bf78-60d29dcf463b"
    }
  ]

Inventory Instance schema: https://github.com/folio-org/mod-inventory-storage/blob/master/ramls/instance.json
Honeysuckle bugfest environment: https://bugfest-honeysuckle.folio.ebsco.com/