doc: autogenerate a list of authors and hall of fame

This adds a build-time option to automatically generate a list of
authors from git history, and includes it in the documentation by
reading the output from git in a Sphinx extension. When git isn't
available or the project source doesn't appear to be a git checkout, the
list is not generated and gracefully replaced with a message explaining
its absence.

Change-Id: I1e9634a90e84262aafd80590deba9875f4b71a3c
Signed-off-by: Peter Marheine <pmarheine@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/86350
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>

doc/conf.py

@@ -3,7 +3,13 @@
 # For the full list of built-in configuration values, see the documentation:
 # https://www.sphinx-doc.org/en/master/usage/configuration.html
 
-import os
+import sys
+
+from pathlib import Path
+
+
+sys.path.append(str(Path('_ext').resolve()))
+
 
 # -- Project information -----------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
@@ -18,7 +24,8 @@ author = 'The flashrom authors'
 master_doc = 'index' # this is needed for old versions
 
 extensions = [
-    'sphinx.ext.todo'
+    'sphinx.ext.todo',
+    'flashrom_authors'
 ]
 
 #templates_path = ['_templates']