Alert on mismatch plugin names

When configuring external plugin, the plugin stanza needs to reference the binary name. Though sensible, it's common to use different conventions to refer to a plugin name vs the binary; the nomad team congenitally calls the LXC plugin as `lxc`, but have the binary called `nomad-driver-lxc`.

When the names are mismatched, the plugin launches with the default configuration and silently drop the operator configuration. This is very confusing and hard to debug.

In the case of LXC, operators may prefer to refer to lxc plugin in config simply as `lxc` but have the binary name be different to avoid collision with the actual `lxc` utility.

Consider the following:
* Warn against used plugin client configuration that doesn't match a running plugin
* Improve the name matching to support common convention for binary names to avoid name conflicts.

Start by tracing how external plugin client configuration is matched to a running plugin and how the plugin binary is launched. Compare the configured plugin name with the binary name, using the LXC example as the motivating case. Done means mismatches no longer silently discard operator configuration, with either a clear warning or supported name conventions.

Written by the indexing model from the issue text.