Introduce a utility module which handles SpecVersion
comparators for an easier SpecVersion maintainance
within the UI5 Tooling source code.
This utility is a kind of semver compatibility layer which
allows using semver functions with the SpecVersion
typical format "Major.Minor".

JIRA: CPOUI5FOUNDATION-224

Add factory function to Specification class

Static methods now create an instance and always throw for unsupported
versions (except isSupportedSpecVersion)

… specVersion string

Co-authored-by: Günter Klatt <57760635+KlattG@users.noreply.github.com>

Use it as the main representation of a specification version (instead of
the raw string as before). This also helps motivate the use of the
helper functions to compare the version. Which is the most common use of
the specification version anyways.