Define a sqlalchemy using parameters instead url

[piraz]

Define a sqlalchemy using parameters instead url.

Paremeters are:

• db or database
• driver
• host
• pass or password
• port
• user or username

This method will be helpful when we have a '@'(for instance) in the password. With the url parameter only that will cause an error while connecting to the database. The password will be always url quoted to avoid this kind of problem.

We could fix the url also but that this will be covered in another ticket.

For an url based datasorce like this:

data:
  sources:
    - name: storage
      connector: sqlalchemy
      dialect: postgresql+psycopg2://myuser:thepassword@127.0.0.1:5432/thedatabase

We can use this kind of representation:

data:
  sources:
    - name: storage
      connector: sqlalchemy
      dialect: postgresql
      driver: psycopg2
      username: myuser
      password: thepassword
      host: 127.0.0.1
      port: 5432
      database: thedatabase

The strategy here is to convert the parameters to it's respective url notation with password being always url quoted.

Let's do the happy path with this ticket and handle mandatory parameters exceptions later.