funccount rename to count

When I wrote funccount, it traced kernel function calls only, but I expected we'd add user-level functions as well. Hence the name. But Sasha not only added uprobes, but also tracepoints and USDT. Now it does more than count functions, it counts everything. Should I rename it to "count"?

I really like how trace is called trace. And these tools are similar, accepting events described in the same way. It sounds more consistent to have them as trace and count.

This is going to break anyone who has automated it, or has learned funccount (and I've written a lot of documentation that calls it funccount). I'd propose adding a shell wrapper called funccount that did:

```shell
echo "NOTICE: funccount is now called count. Executing count."
if [ -e count.py ]; then
./count.py "$@"
else
./count "$@"
fi
```

So this transition would not be painful.

@goldshtn @yonghong-song ... I'll file a separate ticket for argdist. :-)

Review the count.py and count entry points, then locate the documentation that still calls the tool funccount. Check how the proposed shell wrapper would preserve existing invocations and how related tools such as trace are named. Done means the rename and compatibility transition have maintainer agreement, with affected documentation identified.

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