Add TLS verification support

[LHozzan]

Logstash have support to expose JSON metrics via secured monitoring API endpoint, but LogstashExporter not support that setup.

LogstashExporter also not support expose metrics via HTTPS scheme. After discuss in the issue, communication between exporter and Prometheus must be secured as well.

Please add support for:

• read Logstash endpoint protected by TLS
• expose Prometheus metrics endpoint protected by TLS

[github-actions]

This issue has been marked as stale because it has not had activity for 180 days. It will be closed in 7 days if no further activity occurs.

[LHozzan]

Interest for enhancement is still valid.

[sidallet]

Interest for enhancement as well

[Ronnieeeone]

Interest for enhancement as well