Prepare RCP app for multiproject build

Provided that we already configured RCP products, we can now prepare RCP app for multiproject build.

1. Create "build.gradle" in "tutorials" folder (parent of "MyRcpApp" folder)

2. Move "buildscript" and "repositories" from "tutorials/MyRcpApp/build.gradle" to "tutorials/build.gradle", so that two scripts look like this:

"tutorials/build.gradle":

buildscript {
  repositories {
    mavenLocal()
    jcenter()
  }
  
  dependencies {
    classpath 'org.akhikhl.wuff:wuff-plugin:0.0.1'
  }
}

subprojects {
  repositories {
    mavenLocal()
    jcenter()
  }
}

"tutorials/MyRcpApp/build.gradle":

apply plugin: 'java'
apply plugin: 'eclipse-rcp-app'
  
products {
  product platform: 'linux', arch: 'x86_32'
  product platform: 'linux', arch: 'x86_64'
  product platform: 'windows', arch: 'x86_32'
  product platform: 'windows', arch: 'x86_64'
  archiveProducts = true
}

6.3. Create "settings.gradle" in "tutorials" folder (parent of "MyRcpApp" folder), insert code:

include 'MyRcpApp'