Create table uses "contains" instead of exact match

[sophierm]

Describe the bug
When trying to create a new table, the method searches whether the table is already in the catalog. Here, if the table name is a subset of a table name that is already in the catalog the table creation fails.

To Reproduce
Steps to reproduce the behavior:

1. Create table "test123"
2. Create table "test"
   -> no new table is created and the function returns none - nothing happens

Expected behavior
Table creation should work for all table names that do not exactly match a table already in the catalog.
We would expect more meaningful returns: return at least "true" or "false" values and even better, logging the reason why a table creation fails / throw exception.

Screenshots
ibmcloudsql/catalog_table.py

line 288