ENH: allow saving wide dataframes to hdf with format table
based on #11788
closes #6245

This PR allows to save wide dataframes to hdf. It will break forward compatibility, old versions of pandas will not be able to read hdfs from new versions.
The column is saved to a vlarray with object atomic. This is rather slow for very wide dfs but does not require any type checks.
One test fails because the saved column is not compressed but the compression level is checked for all nodes. I think this is fine but i wanted to consult with you before rewriting the test.

Two tests were added to check if a wide df can be saved and if it is appendable.

Please let me know what you think and if there is additional need for test coverage.