Added 5 Islamic Books to library/islam

[AbdulRehmanAsif-21]

Summary

Added 5 Islamic Books to the repo in pdf format

Library changes (REQUIRED)

library/islam/ulum-al-qur-an-an-introduction-to-the-sciences-of-the-qur-an.pdf
library/islam/the-excellent-qualities-of-the-holy-qur-an.pdf
library/islam/ARcauses-that-aid-in-the-memorization-of-the-qur-an.pdf
library/islam/ARthe-three-shelters-tafseer-of-the-three-quls.pdf
library/islam/ARalliance-disavowal.pdf

Checklist (all required)

• I confirm this PR includes at least 5 books in the library (files in library/ and entries in books.json).
• I updated any relevant docs or README if the structure changed.
• The repository builds/tests (if applicable) pass locally.