Allow height padding to be defined

[Kieranties]

Is your feature request related to a problem? Please describe.
Allow the padded height to be specified in the configuration file both as a specified default and as a token rule.

Describe the solution you'd like
The configuration should allow the default padding to be specified for each format. Specifying for a format will force the result to use the padded value.
Each format may specify it's own height

{
  "Formats" : {
    "Semver1" : {
        HeightPadding: 5
    }
  }
}

Additionally, the height token should allow the padding to be specifically overridden using {height:7}