quote driver name and pass-through keys in pyodbc connect string

quote driver name and pass-through keys in pyodbc connect string

Tightened the construction of the ODBC connection string in the pyodbc
connector (as well as the mssql-python connector in 2.1) so that the
driver name, the names of pass-through connection parameters, and values
containing ``}`` are brace-quoted.  Previously a ``}`` in the driver name
or in a pass-through value, or a ``;`` in the name of a pass-through
parameter, could close the surrounding token early and allow the
remainder of the string to be interpreted as additional connection
attributes.  Pull request courtesy dxbjavid.

Fixes: #13380
Closes: #13379
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/13379
Pull-request-sha: 34433408bff86a9044be5d431b31688ab6d7578d

Change-Id: I5a0b522e62d306cf6dc59c7f61fe584df02a948d
(cherry picked from commit 8604972666978ca981623c7f415e405bc074663a)