Add .git-blame-ignore-revs file

Contains the list of commits to ignore for `git blame`.
For now, there are two commits:
- the commit which reformatted all source files to comply with PEP8 and
- the commit that removed wildcard imports.

Usage:
    git blame --ignore-revs-file .git-blame-ignore-revs

The name is chosen on purpose as it is supported by GitHub [1].

[1] https://docs.github.com/en/repositories/working-with-files/using-files/viewing-a-file#ignore-commits-in-the-blame-view

.git-blame-ignore-revs

@@ -0,0 +1,5 @@
+# .git.blame.ignore.revs
+# Formatted the entire codebase to comply with PEP8
+5610b63dbd9d5d8d6b61242ec722615bf61ac5a3
+# Removed wildcard imports
+84cf63640204639fd2ae4fdcae64cadfb81805d1