Add metrics logs provider configuration

[NipunaMadhushan]

Purpose

We need to implement log based metrics for Ballerina as a requirement for all WSO2 on-prem and SaaS products that need to use the same stack for observability. In order to retrieve metrics data using OpenSearch, we need to provide log based metrics which contain a format as follows.

[Time Stamp] protocol:<protocol_type>, tagKey1:tagValue1, tagKey2:tagValue2, .. | response_time:<value_in_seconds>

This feature is configurable in runtime and can be configured as follows in the Config.toml for the ballerina/observe module. By default, this configuration will be false.

[ballerina.observe]
metricsLogsEnabled=true
metricsLogsProvider="metricsLogsProvider"

Fixes ballerina-platform/ballerina-lang#43614

Examples

Checklist

• Linked to an issue
• Updated the changelog
• Added tests