[🐞 Bug]: Bugs in concrete cover check workflow

[SZeltaat]

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Issue description

• Dealing with 50+ years design lifetime is wrong in table_4_3.py
• Indentation for lateX representation concrete cover check and improved lateX syntax
• lateX representation mistake table 4.3 -> table 4.4 in nominal_concrete_cover.py
• "\ge " instead of "≥" in lateX rep. in nominal_concrete_cover.py
• make delta c dev adjustable in constants

Reproducible example

Expected behavior

Installed versions