fix: improve haproxy dashboard legends

Some of the panels within the `haproxy` dashboard contain legends that
do not include enough information to distinguish between services or
servers.

For example:

```
IN Front
IN Front
IN Front
```

turns into:

```
IN Front capi01
IN Front capi02
IN Front capi03
```

Signed-off-by: Jack Hodgkiss <jack@stackhpc.com>

Author: jackhodgkiss