Generate MARC bib record - Instance electronic access

Purpose/Overview:
FOLIO inventory instance contains electronic access element that will need to be mapped to the specific MARC fields while generating a record on the fly.

Requirements/Scope:
Fields

1. Link text - 856 subfield $y
2. Materials Specified - 856 subfield $3
3. URI - 856 subfield $u
4. URL public note - 856 subfield $z
   The subfieds should be arranged in the alphabetical order, followed by numeric subfields

Indicators
Indicators are being used to determine the URL relationship. First indicator is set to 4.

1. URL relationship Resource - 2nd indicator is set to 0
2. URL relationship Version of Resource - 2nd indicator is set to 1
3. URL relationship Related resource - 2nd indicator is set to 2
4. everything else - second indicator is blank

For the details of the mapping refer to Recommended MARC mapping spreadsheet: https://docs.google.com/spreadsheets/d/11lGBiPoetHuC3u-onVVLN4Mj5KtVHqJaQe4RqCxgGzo/edit#gid=1166940623 Instance to MARC tab.

Approach:

Acceptance criteria:

1. The generated record is short-lived and generated each time it is requested
2. The specified identifiers are being correctly mapped according to the mapping document:
3. The record is saved in .mrc file and contains correctly populated data
4. Unit tests are written
5. API tests are written