Update exporters: migration to CharmHub

Also, added kafka_endpoint config to kafka exporter

Change-Id: I24459e33841da33455b6780a4de2c808ddf30d0b
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charm/mysqld-exporter/src/charm.py b/installers/charm/mysqld-exporter/src/charm.py
index 46588b9..153dbfd 100755
--- a/installers/charm/mysqld-exporter/src/charm.py
+++ b/installers/charm/mysqld-exporter/src/charm.py
@@ -209,7 +209,7 @@
             config.image_pull_policy,
             run_as_non_root=config.security_context,
         )
-        container_builder.add_port(name=self.app.name, port=PORT)
+        container_builder.add_port(name="exporter", port=PORT)
         container_builder.add_http_readiness_probe(
             path="/api/health",
             port=PORT,