Add support for NPT_F AIMD of cp2k version 7.1

[coveralls]

Pull Request Test Coverage Report for Build 7330398212

• 11 of 17 (64.71%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+1.3%) to 38.584%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cp2kdata/output.py	4	6	66.67%
cp2kdata/block_parser/cells.py	7	11	63.64%
<!--	Total:	11	17	64.71%	-->

Totals
Change from base Build 7200732113:	1.3%
Covered Lines:	752
Relevant Lines:	1949

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💛 - Coveralls