quickMARC performance optimization

After completed integration with records storage / change manager:

• Refactor existing code to avoid http client creation for each request (https://vertx.io/docs/vertx-core/java/#_httpclient_usage)
• Refactor and optimize QuickMarcJson <-> ParsedRecord converter

Acceptance criteria:
1) One instance of Vert.X HttpClient (https://vertx.io/docs/vertx-core/java/#_httpclient_usage) is used for all application;
2) Performance improvement confirmed by using performance script https://github.com/folio-org/folio-perf-test/tree/master/Folio-Test-Plans/mod-quick-marc;
3) QuickMarcJson <-> ParsedRecord converters are refactored;
4) Performance improvement is confirmed by microbenchmarking (possibly, JMH Framework).