Introduce a feature to propagate the machine name to user data and as label to the node

[oliver-goetz]

What this PR does / why we need it: This PR adds two new features to MCM which are required to enable node-agent-authorizer webhook based authentication for gardener-node-agent. Please see https://github.com/gardener/gardener/pull/10014

• MCM replaces the magic string <<MACHINE_NAME>> in user data with the name of the machine when it is bootstrapped.
• MCM adds the name of the machine to node.gardener.cloud/machine-name label of the corresponding node.

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

Release note:

MCM replaces the magic string `<<MACHINE_NAME>>` in user data with the name of the machine when it is bootstrapped.

MCM adds the name of the machine to `node.gardener.cloud/machine-name` label of the corresponding node.

[oliver-goetz]

Thanks for reviewing. I just applied your feedback.