Update: nodeSelector

The other has been deprecated since kubernetes v1.14

Upgrade CRA, webpack5, storybook 4.6

charts: Update to Headlamp 0.9.0

github: Fix golang version to be 1.17 rather than latest

headlamp-plugin 0.4.8

Plugin: allow cluster chooser button overriding

Add clusters dynamically

We also add the infrastructure on redux store to add the chooser button
component

This patch adds a new setCluster method to the lib/Headlamp class.

This patch adds test coverage to the dynamic cluster creation, and
for that the code that creates the Headlamp base HTTP handler had to
be also abstracted into its own function and started without failing
if kubeconfigs are not found.

We want plugins to set up clusters dynamically, i.e. to have a new
backend endpoint to tell it about clusters that do not come from the
kubeconfig files.

Instead of keeping a list of clusters around when we have already that
information as part of the contextProxies var, we should instead just
dynamically get the clusters from the latter.

This will also make the /config endpoint accurate when we start
adding clusters dynamically.

These changes keep the needed contexts and respective proxy set ups
in a map which is used dynamically when a cluster API request is
received. This doesn't change the previous behavior of Headlamp but
makes things simpler to later add clusters dynamically.

helm chart: Support deploying the ServiceAccount in different namespaces

Co-authored-by: S Santhosh Nagaraj <nssvlr@gmail.com>

plugins: Use dev headlamp-plugin when testing examples

app: Update electron to 13.6.9

Implement new cluster chooser style

frontend: Add router to pluginLib

There was a typo (capital N).

A method is better in terms of dev ex here.

We want all the route related methods to be used by plugin developers
thus exporting this in the pluginLib makes sense.

Add notification area

build(deps): bump async from 2.6.3 to 2.6.4 in /frontend

build(deps): bump ejs from 3.1.6 to 3.1.7 in /app