Add .gitignore file for Curry

[matthesjh]

Reasons for making this change:

The Curry.gitignore file contains the files and folders that should be ignored when working with the functional logic programming language Curry. The listed files and folders are generated by the compilers and the package manager.

Links to documentation supporting these rule changes:

• Manual of the Curry compiler KiCS2
• Manual of the Curry compiler PAKCS
• Manual of the Curry package manager CPM

If this is a new template:

• Link to application or project’s homepage: https://www.curry-lang.org/

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