Support database.url for PostgreSQLConnector [DBZ-5771]

Migrated from [DBZ-5771](https://issues.redhat.com/browse/DBZ-5771)

h2. What Debezium connector do you use and what version?

PostgreSQL Connector 2.0
h1. Feature request or enhancement

For feature requests or enhancements, provide this information, please:
h2. Which use case/requirement will be addressed by the proposed feature?

I am trying to start an embedded Debezium Engine in my Spring Boot application. I configure Spring Boot by giving it a property which contains the URL, ie. 
{{dbc:postgresql://127.0.0.1:5435/mydatabase}}. To start Debezium I need to split that URL to get to the properties I need ({{{}database.hostname{}}}, {{{}database.port{}}}, {{{}database.dbname{}}}).

It would be easier to just pass the URL to Debezium instead of the parts. 
h2. Implementation ideas (optional)

I see {{io.debezium.connector.postgresql.connection.PostgresConnection}} uses a pattern based factory to create the jdbc url from the given properties. It should be possible to use a patternfactory or urlfactory based on the given properties. Use the url if given, otherwise use the other properties to create the url based on the pattern.

Start with io.debezium.connector.postgresql.connection.PostgresConnection and trace how database.hostname, database.port, and database.dbname are used to create the JDBC URL. Done means the PostgreSQL Connector accepts database.url while retaining the existing property-based URL construction when database.url is absent.

Written by the indexing model from the issue text.