A way to set plugin version, vendor name and url

Introduced 3 proprties:

- teamcity.${artifactId}.plugin.version
- teamcity.${artifactId}.plugin.vendorName
- teamcity.${artifactId}.plugin.vendorUrl

where ${artifactId} is project's artifactId. These properties could be defined during the project build to specify plugin version, vendor name and vendor url. eg:

mvn package -Dteamcity.sample.plugin.version=1

Unset property will use default value.