Add Concept Exercise: annalyns-infiltration

[0xNeshi]

Towards #103

Scaffold https://github.com/exercism/cairo/blob/main/exercises/concept/annalyns-infiltration

TODO:

Use Go's implementation as inspiration for code and metadata files https://github.com/exercism/go/tree/main/exercises/concept/annalyns-infiltration

• implement instructions.md
• implement introduction.md
• implement hints.md
• implement ./meta/design.md
• implement the example solution in .meta/exemplar.cairo
• implement src/lib.cairo
• implement tests tests/annalyns_infiltration.cairo
• replace <your_gh_username> placeholder with your actual GH username in .meta/config.json
• add missing blurb to .meta/config.json