It is difficult to customize the TinkerbellTemplateConfig

**What would you like to be added**:
I would like to be able to add tasks to the TinkerBellTemplateConfig without having to take ownership of the entire TinkerbellTemplateConfig. Currently the workflow is full of sha values and versions I do not want to be responsible for. Currently, I have to become responsible for every sha and version in the file if all I want to do is add an NTP configuration task.

**Why is this needed**:
The [current template](https://anywhere.eks.amazonaws.com/docs/reference/clusterspec/baremetal/#ubuntu-tinkerbelltemplateconfig-example) is too much responsibility when I want to add a workflow task.

Also, getting the current template is not documented. It is expected to get it from the bootstrap cluster with `kind get wf` but that is not documented. Many folks are inclined to copy and paste the config from here, but it is very out of date.

Start with the TinkerbellTemplateConfig definition and the documented Ubuntu TinkerbellTemplateConfig example. Run `kind get wf` on a bootstrap cluster to compare the current workflow with the stale example. Done means users can add a task without owning unrelated SHA values and versions, and the way to retrieve the current template is documented.

Written by the indexing model from the issue text.