proxy-scanner chart - it should be possible to use existing secret to provide certs

[d-mankowski-synerise]

Right now, the logic in proxy-scanner chart is as follows:

• always create a secret
• if skipCert is set to false, then add data to this secret

This logic is broken, because of 3 reasons:

• deployment of chart will always create a resource, even if does not contain any data (or overwrite existing secret)
• it forces to key in plain text (certs.serverKey)
• name of the secret is fixed ({{ .Values.name }}-certs)

Instead, it should work like in lacework-agent, where it is possible to provide name of existing secret (https://github.com/lacework/helm-charts/blob/main/lacework-agent/templates/daemonset.yaml#L61)