Improve robustness of parsing versions and element names from UPF files

[astamminger]

Fixes #2228

Changed parsing behavior such that regular expressions for elements and versions are now matched against the whole file instead of matching line by line. This makes the parsing process more robust and allows for parsing desired quantities independent of the actual position of the UPF file (See for instance the additional header line mentioned in issue #2228). Since re.search() returns the first match found in the string, there is no major performance impact expected compared to the previous implementation.

[sphuber]

It would be good if you could add some tests that test the old failure

[astamminger]

It would be good if you could add some tests that test the old failure

@sphuber Added required tests to check the parser function (Hope they are in the right place)

[coveralls]

Coverage increased (+0.02%) to 68.957% when pulling 947ad22 on boschresearch:issue_2228 into c96b78e on aiidateam:provenance_redesign.