[llvm] workflows: Add some automation for commit access requests (PR #123113)

[Aiden Grossman via llvm-commits]

================
@@ -241,6 +249,57 @@ def run(self) -> bool:
         return True
 
 
+class CommitRequestGreeter:
+    def __init__(self, token: str, repo: str, issue_number: int):
+        self.repo = github.Github(token).get_repo(repo)
+        self.issue = self.repo.get_issue(issue_number)
+
+    def run(self) -> bool:
+        # Post greeter comment:
+        comment = f"""
+@{self.issue.user.login} thank you for apply for commit access.  Please  review the project's [code review policy](https://llvm.org/docs/CodeReview.html).
+"""
+        self.issue.create_comment(comment)
+
+        # Post activity summary:
+        total_prs = 0
+        merged_prs = 0
+        merged_by = {}
+        reviewed_by = {}
+        for i in self.repo.get_issues(creator=self.issue.user.login, state="all"):
+            issue_reviewed_by = set()
+            try:
+                pr = i.as_pull_request()
+                total_prs += 1
+                for c in pr.get_review_comments():
+                    if c.user.login == self.issue.user.login:
+                        continue
+                    issue_reviewed_by.add(c.user.login)
+                for r in issue_reviewed_by:
+                    if r not in reviewed_by:
+                        reviewed_by[r] = 1
+                    else:
+                        reviewed_by[r] += 1
+                if pr.is_merged():
+                    merged_prs += 1
+                    merger = pr.merged_by.login
+                    if merger not in merged_by:
+                        merged_by[merger] = 1
+                    else:
+                        merged_by[merger] += 1
+                    continue
+
+            except github.GithubException:
+                continue
+
+        comment = f"""
+### Activity Summary:
----------------
boomanaiden154 wrote:

Same here.

https://github.com/llvm/llvm-project/pull/123113