Dsdbmanager

- no breaking changes
- mysql and mssql doesn't always use database names in connection string. I encountered cases like these recently so I added a boolean field
when adding new databases. The field `use_dbname_to_connect` should be `True` if user wants database name to be used in database connection and `False` otherwise.
This change should only impact mysql and mssql connections.

- no breaking changes
- snowflake connection is rather different so changes were made so that user can enter all snowflake specific connection parameters
- If users want to use the snowflake connection object, they can use a `raw_connection` argument in `dsdbmanager.snowflake_.Snowflake.create_engine`

- sqlalchemy_engine is read only
- host, credential and key attibutes of configurer are read only
- user can now create subsets. In the root folder where host is created, you will have a `subsets` folder. the goal is to be able to create different subsets for each project. Say I have 10 databases, 5 oracle and 5 mysql but I only need 2 each for a specific project. You can create a subset with a totally different encryption key that you can use on the server you want the project to run.

the manifest file has been added and a wheel file created

There was a bug with the way credentials were stored. This caused the whole credential branch
for a dialect to be replaced. It has been fixed