Improve GitHub Actions

[filiphr]

• Use maven wrapper in actions
• Use --no-transfer-progress, which avoids download progress tracking in logs
• Do not run conformance, docs and publish snapshot worfklows on forks

The --no-transfer-progress avoids output like:

Downloading from maven-central: https://repo.maven.apache.org/maven2/io/projectreactor/reactor-bom/2024.0.0/reactor-bom-2024.0.0.pom
Progress (1): 911 B
Progress (1): 2.3 kB
Progress (1): 4.8 kB
                    
Downloaded from maven-central: https://repo.maven.apache.org/maven2/io/projectreactor/reactor-bom/2024.0.0/reactor-bom-2024.0.0.pom (4.8 kB at 7.2 kB/s)
Downloading from maven-central: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-dependencies/4.0.2/spring-boot-dependencies-4.0.2.pom
Progress (1): 1.0 kB
Progress (1): 2.3 kB
Progress (1): 4.3 kB
Progress (1): 6.5 kB
Progress (1): 8.3 kB
Progress (1): 11 kB 
Progress (1): 15 kB
Progress (1): 20 kB
Progress (1): 30 kB
Progress (1): 38 kB
Progress (1): 42 kB
Progress (1): 51 kB
Progress (1): 61 kB
Progress (1): 71 kB
Progress (1): 92 kB
Progress (1): 111 kB
Progress (1): 116 kB
Progress (1): 123 kB
Progress (1): 131 kB
Progress (1): 136 kB
Progress (1): 137 kB
                    
Downloaded from maven-central: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-dependencies/4.0.2/spring-boot-dependencies-4.0.2.pom (137 kB at 2.4 MB/s)
Downloading from maven-central: https://repo.maven.apache.org/maven2/org/apache/activemq/activemq-bom/6.1.8/activemq-bom-6.1.8.pom
Progress (1): 799 B
Progress (1): 1.9 kB
Progress (1): 7.9 kB