support uri=True in monetdbe.connect

[gijzelaerr]

sqlite supports this:

https://docs.python.org/3/library/sqlite3.html#sqlite3.connect

If uri is true, database is interpreted as a URI. This allows you to specify options. For example, to open a database in read-only mode you can use:

db = sqlite3.connect('file:path/to/database?mode=ro', uri=True)

[njnes]

should be handled on the python side. monetdbe_open only handles the extra structure with a limited set off options