Add bitbake extensions and files

Files and extentions of bitbake are taken from the tool
documetantion [1].

[1] https://docs.yoctoproject.org/bitbake/2.6/bitbake-user-manual/bitbake-user-manual-metadata.html

Author: vlotorev

identify/extensions.py

@@ -13,6 +13,9 @@
     'bat': {'text', 'batch'},
     'bats': {'text', 'shell', 'bash', 'bats'},
     'bazel': {'text', 'bazel'},
+    'bb': {'text', 'bitbake'},
+    'bbappend': {'text', 'bitbake'},
+    'bbclass': {'text', 'bitbake'},
     'beancount': {'text', 'beancount'},
     'bib': {'text', 'bib'},
     'bmp': {'binary', 'image', 'bitmap'},
@@ -343,6 +346,8 @@
     '.zshrc': EXTENSIONS['zsh'],
     '.zshenv': EXTENSIONS['zsh'],
     'AUTHORS': EXTENSIONS['txt'],
+    'bblayers.conf': EXTENSIONS['bb'],
+    'bitbake.conf': EXTENSIONS['bb'],
     'BUILD': EXTENSIONS['bzl'],
     'Cargo.toml': EXTENSIONS['toml'] | {'cargo'},
     'Cargo.lock': EXTENSIONS['toml'] | {'cargo-lock'},