fix the broker stats with different environments

[bpereto]

Motivation

the current state of the master branch does not work for broker stats (they are empty) and collecting is failing with exceptions.
Probably because of the implementation how the BrokerStatsImp finds the broker for a specified cluster.

Currently, there are multiple problems:

• If the Service URL differs from the broker urls, then the corresponding token for authentification is not found. ex: service url https://brokers.pulsar.internal:8443 found brokers: http://broker01.pulsar.internal:8080 even the brokers are configured with tls. the environment token is then not found for broker01, it matches only brokers.pulsar.internal.
• enabling TLS with tls.enabled enables not only TLS-Transport-Encryption, it configures TLS Client Auth, which is not in all scenarios needed or wanted. I would like to have TLS Cmmunication and Token-Auth.
• Broker URL Schema is not handled well - addition of http:// or https:// is scattered.

the changes contained in this pull request should sufficiently fix broker metric collection for TLS+TokenAuth (not TLS Client Auth) environments.

Modifications

• allow specification of environment at broker stats collection to get the token
• build the broker url with schema, port from specified service url. this enables the use of TLS.
• specify environment and environment token when collecting stats with collectStatsToDB
• fix axios parameter serialization which default behaviour was changed in 1.0
• updated hikari parameters for attempt to limit pool exhaustion exceptions

Verifying this change

• Make sure that the change passes the ./gradlew build checks.

[lhotari]

• If the Service URL differs from the broker urls, then the corresponding token for authentification is not found. ex: service url https://brokers.pulsar.internal:8443 found brokers: http://broker01.pulsar.internal:8080 even the brokers are configured with tls. the environment token is then not found for broker01, it matches only brokers.pulsar.internal.

btw. This is related to some gaps in the Pulsar API. In the past brokers didn't have a stable unique identifier. In PR apache/pulsar#21894, the "lookupServiceAddress" was renamed to be "brokerId" so that there would be a single unique identifier for a broker in a cluster. This is WIP and apache/pulsar#22647 adds brokerId to lookup results. There are a few more APIs to cover to make the brokerId the unique id for a broker.

[lhotari]

LGTM, thanks for the contribution @bpereto