Do not append groupId/artifactId to the url in children

[wendigo]

Before:

./mvnw help:effective-pom -pl ':trino-mysql' | grep 'url>' | head -n 1
Running `/Users/mateuszgajewski/Projects/src/github.com/trinodb/trino/mvnw`...
  <url>https://trino.io/plugin/trino-mysql</url>

After:

./mvnw help:effective-pom -pl ':trino-mysql' | grep 'url>' | head -n 1
Running `/Users/mateuszgajewski/Projects/src/github.com/trinodb/trino/mvnw`...
  <url>https://trino.io</url>

According to the project.url documentation in the Maven xsd:

<xs:documentation source="description">
            The URL to the project's homepage.
            <br><b>Default value is</b>: parent value [+ path adjustment] + (artifactId or project.directory property), or just parent value if
            project's <code>child.project.url.inherit.append.path="false"</code>
          </xs:documentation>

This invalid url (https://trino.io/core/trino-server) was added to the RPM as URL metadata field.

[wendigo]

It seems that most of the uris were incorrect @martint (we inherited some from airlift/airbase)