that manages the steps sequence.

 The sequence is divided into 2 phases:

 * phase 1

   ** profile activation: see {{{./apidocs/org/apache/maven/model/profile/activation/package-summary.html}available activators}}.
   Notice that model interpolation hasn't happened yet, then interpolation for file-based activation is limited to
   <<<$\{basedir}>>> (since Maven 3), <<<$\{rootDirectory}>>> (since Maven 4), system properties and user properties

* installation
* activation
* update
* deactivation
* un-installation

When a plugin is installed we may want to check the license and make users agree. We may also want to unpack the given plugin in a particular location.