percona: adapt upstream release model

In accordance to the upstream release cycle, we now provide 2 flavours
of the percona mysql ecosystem. The default is the LTS variant,
additionally there is now the floating `percona-server_innovation`
always pointing to the most recent regular release.

- mentioned in release notes
- adapted all depending tests and tools (xtrabackup)

nixos/tests/mysql/common.nix

@@ -4,7 +4,7 @@
     inherit (pkgs) mysql80;
   };
   perconaPackages = {
-    inherit (pkgs) percona-server_8_0 percona-server_8_3;
+    inherit (pkgs) percona-server_lts percona-server_innovation;
   };
   mkTestName = pkg: "mariadb_${builtins.replaceStrings ["."] [""] (lib.versions.majorMinor pkg.version)}";
 }