Add init scripts file name guide for build scan capturing

[KENNYSOFT]

I've experienced the build scan capturing not working sometimes. After some research, I found out that the order of the init script execution matters. This PR adds a guide for the situation.

Structure when failed:

USER_HOME
└── .gradle
    └── init.d
        ├── build-result-capture.init.gradle
        ├── build-result-capture-service.plugin.groovy
        └── scans-init.gradle

Resolved structure, for instance:

USER_HOME
└── .gradle
    └── init.d
        ├── 01-scans-init.gradle
        ├── build-result-capture.init.gradle
        └── build-result-capture-service.plugin.groovy

[hythloda]

@bigdaz will look into this.

[bigdaz]

Thanks for the contribution!