Add wait polling for retrieving redfish storages and systems

[stefanhipfel]

• adds wait polling for retrieving redfish storages. Some vendors redfish resources are not immediately available after a powerOn.
• moves waitForPower function to bmc client

[defo89]

should we make interval and timeout configurable like in bmcClient.WaitForServerPowerState?

[stefanhipfel]

I was thinking about it. We just have so many config options already :)

[Nuckal777]

Superfluos newline. Given the amount of optiones, it may be worth introducing a BMCClientOptions struct to hold all of them.

[stefanhipfel]

I had that already implemented in the las commit (c7bf550).
Some of the settings are mandatory like user/pw, so I wanted to separate them.
Especially since we have some functions where we only need to provide these polling values:
func GetBMCClientFromBMC(ctx context.Context, c client.Client, bmcObj *metalv1alpha1.BMC, insecure bool, polling bmc.PollingOptions)

Username and password are retrieved via the k8s secrets.

[afritzler]

I would also favor for a generic BMCOptions struct which we can extend as we go. That way we don't need to change the method signature too often.