Add node pool

[ograu]

AddNodePool component is basically copy/pasted from CreateCluster component and adapted to its needs: I removed everything related to Azure and KVM because AFAIK node pools aren't supported in Azure and KVM by now. Correct me if I'm wrong, please.

Also in this PR:

• I've started to use Immer to update nested properties on local state object
• I've started to add the HTML element name as a suffix in emotion styled variables. I think Marian does it as well (?). It makes JSX in render easier to read IMO.

Form view:

With validation errors/messages (some adjustments to be made on margins):

[ograu]

ping @marians

Now the form can switch from availability zones picker:

To availability zones labels:

In order to have clickable labels for availability zones I have:

• Adapted AvailabilityZonesLabel and AvailabilityZonesLabels components to accept checked/unchecked state
• Created a wrapper for AvailabilityZonesLabels responsible for passing the state in the correct shape to the form

This is how labels looks like when they are checked (A, B, C) and unchecked (D, E):

[ograu]

• Changed default values for scaling,
• Maximum availability zones is 4 now
• Improved validation and messages to the user for labels

[ograu]

ping @marians Just realized that you weren't added here as a reviewer...

[marians]

Tested together in a hangout and noted a few nitpicks, no blockers found.

[ograu]

In these lasts commits I made the modifications we've been discussing this morning:

• Region: before region
• 0 nodes when no the cluster has no node pools
• Kubernetes endpoint copyable
• Upgrade available underlined when hover
• Added text To enable autoscaling, set minimum and maximum to different values. below picker
• Changed background (too dark in my opinion)
• Disable text selection highlighting in all AZ labels

Things I couldn't change:

• Can't use the region instead AZ because in testing API we don't have the datacenter property on the object retrieved...

And finally, that weird spanis something that ReactCSSTransitionGroup is adding 🤷‍♂

I will merge it and when we have the region will update it.