feat(fastapi): add comment actions to /account/{username}/comments

With this change, we've decoupled some partials shared between
`/pkgbase/{name}` and `/account/{username}/comments`. The comment
actions template now resolves its package base via the `comment`
instance instead of requiring `pkgbase`.

We've also modified the existing package comment routes to
support execution from any location using the `next` parameter.
This allows us to reuse code from package comments for
account comments actions.

Moved the majority of comment editing javascript to its own
.js file.

Signed-off-by: Kevin Morris <kevr@0cost.org>

test/test_packages_routes.py

@@ -1055,6 +1055,13 @@ def test_pkgbase_comments_missing_comment(client: TestClient, maintainer: User,
 
 def test_pkgbase_comments(client: TestClient, maintainer: User, user: User,
                           package: Package):
+    """ This test includes tests against the following routes:
+    - POST /pkgbase/{name}/comments
+    - GET /pkgbase/{name} (to check comments)
+        - Tested against a comment created with the POST route
+    - GET /pkgbase/{name}/comments/{id}/form
+        - Tested against a comment created with the POST route
+    """
     cookies = {"AURSID": maintainer.login(Request(), "testPassword")}
     pkgbasename = package.PackageBase.Name
     endpoint = f"/pkgbase/{pkgbasename}/comments"