Rename presharedKey

[dominic22]

To avoid confusion with the asymSharedKey used to encrypt the state and messages for privatePlus channels we want to rename the presharedKey. In adidtion, rename hasPresharedKey to hasAuditorKey when creating a channel. (CreateChannelPayload)

Since it is used mainly for auditors we will name the presharedKey to auditorKey

• Rename all usages of the key
• Rename in swagger docs
• Rename in the is-ui-components
• Rename in documentation