Fix scienta txt reader

[lukaspie]

• [x] import changed key construction and energy parsing from #5
• [x] use data model to validate types of reader data
• [x] update config file to latest NXmpes
• [x] add example data
• [x] add test data

[coveralls]

Pull Request Test Coverage Report for Build 8480529200

Details

• 171 of 178 (96.07%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+5.7%) to 64.502%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pynxtools_xps/scienta/scienta_txt.py	81	83	97.59%
pynxtools_xps/reader.py	31	36	86.11%
<!--	Total:	171	178	96.07%	-->

Totals
Change from base Build 8465703103:	5.7%
Covered Lines:	2195
Relevant Lines:	3403

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💛 - Coveralls