Add support for Robot Framework Report Publisher

Allow to use DSL as publishRobotFrameworkReports to configure the plugin as a publisher

Resolves JENKINS-21408
Introduce a Context for Robot framework publisher

Based on the number of arguments, introduce a context version of Robot framework publisher helper

Resolves JENKINS-21408
JENKINS-21408 Robot Framework support: Add closure

Add the support to be able to use closures to configure the plugin

Resolves JENKINS-21408
JENKINS-21408 Robot framework, rebase, merge
JENKINS-21408 Remove confusions and refactor

Remove the confusions by only using RobotFrameworkContext and remove configuration

Resolves JENKINS-21408
JENKINS-21408 Use 4-space formatting
JENKINS-21408 Only use a closure to configure

Remove methods with large number of parameters. Allow the use of a closure for configure the plugin. If no closure is provided, the default values are used for Robot framework plugin.

Resolves JENKINS-21408
JENKINS-21408 Apply 4-space formatting
JENKINS-21408 Use Preconditions for validation
JENKINS-21408 Apply 4-space formatting
JENKINS-21408 Use primitive type where possible

This is to avoid not `null` validations
JENKINS-21408 Use a better variable name

Use `context` instead of `ctx`
JENKINS-21408 Remove unnecessary import

In all honesty, I do not know how line has appeared in the change sets