hmccreds.yaml: alternate_hmc and retry attempts capability

[ioioioioioioioioioioioioio]

In the hmccreds.yaml file please consider updating to allow attempts to reach a secondary alternate HMC/HMA if the primary fails. This can be achieved via the following concept.

create new fields:
primary_hmc = IP or hostname of primary HMC/HMA
primary_hmc_userid
primary_hmc_password
primary_hmc_verify_cert

alternate_hmc = IP or hostname of the alternate HMC/HMA
alternate_hmc_userid
alternate_hmc_password
alternate_hmc_verify_cert

hmc_retries = Number of attempts to reach the primary_hmc unsuccessfully before attempting the alternate_hmc
hmc_retries_interval = Number of seconds to wait in between hmc_retries attempts

Example of behavior at startup:
If the exporter starts and it is unable to reach the primary_hmc after 5 attempts where each attempt waits 30 seconds, it will then attempt to reach the alternate_hmc. this is if hmc_retries = 5 and hmc_retries_interval = 30

Example of behavior during task operation:
If the exporter, while running, loses connection to the current hmc, it will try to connect 5 times with 30 second wait in between each attempt to the existing HMC before it tries to reach the other one. In this scenario, it may be on the alternate_hmc or the primary_hmc. The goal is that it will try the other one if it loses connection during operation.

This will improve the robustness and data collection for when there are service events on the HMA/HMC such as microcode or breakfix.