ConfigPackageUtility::ValidateName: replace broken regex

[julianbrost]

The old validation regex matched if the name consists only of invalid character, not that it does not contain them, i.e. something like "foo/bar" was considered valid.

This commit replaces the regex with a check that all characters in the name are allowed characters.

Backwards compatibility

This change could cause trouble in existing installations as package names could have worked before that weren't supposed to be valid. We could also be more permissive then what I suppose was intended with the original implementation.

Before

Running the new tests with the old implementation:

/home/jbrost/dev/icinga2/test/remote-configpackageutility.cpp(21): error: in "remote_configpackageutility/ValidateName": 'foo.bar' should not be valid
/home/jbrost/dev/icinga2/test/remote-configpackageutility.cpp(21): error: in "remote_configpackageutility/ValidateName": 'foo/bar' should not be valid
/home/jbrost/dev/icinga2/test/remote-configpackageutility.cpp(21): error: in "remote_configpackageutility/ValidateName": 'foo:bar' should not be valid

After

New tests pass