feat!: kpiId type changed from enum to string

[janniclas]

To verify the correctness of the changes I ran the local tests in SPHA.
Further, I integrated the changed version with both, the data-provider, and SPHA-CLI and made the necessary changes to support the type change. See fraunhofer-iem/spha-cli#23 for how this change affects client code.

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
JUnit Test Report	78 ran	78 passed	0 skipped	0 failed

[github-actions]

Code Coverage

Overall Project	79.38% -1.03%	🍏
Files changed	65.52%	❌

Module	Coverage
core	83.36%	🍏
adapter	76.16% -1.86%	❌

Files

Module	File	Coverage
core	KpiHierarchyNode.kt	99.71%	🍏
adapter	CveAdapter.kt	100%	🍏
	TlcAdapter.kt	89.55%	🍏
	TrufflehogAdapter.kt	88.89%	🍏
	VcsAdapter.kt	0% -12.12%	❌
	OccmdAdapter.kt	0% -33.68%	❌

[jusito]

LGTM
mostly renaming beside KpiHierarchyNode, different hierarchies are tested so no additional test required, tests are fine so am I.