Include planning time in datafusion-cli printing

[Dandandan]

Which issue does this PR close?

Closes #859

Rationale for this change

Planning / retrieving statistics / etc can take a considerable time. This makes the cost more visible.

Before:

> CREATE EXTERNAL TABLE lineitem STORED AS PARQUET LOCATION './lineitem/';
0 rows in set. Query took 0.000 seconds.

After:

> CREATE EXTERNAL TABLE lineitem STORED AS PARQUET LOCATION './lineitem/';
0 rows in set. Query took 1.999 seconds.

What changes are included in this PR?

Just moving the retrieval of start time before the sql call.

Are there any user-facing changes?

[alamb]

Ooof -- 2s to load stats. 👍 for making it more visible