Create a migrations page

[ggam]

When BC is broken, a context param is added to restore the old behavior. Unfortunately, that context params are scattered throughout the docs. A new page should be added stating the BC breaks and context params for each version.

[stephanrauh]

Let's gather some points to be mentioned:

• b:datePicker is deprecated since 1.1.0. Start using b:dateTimePicker.
• b:slider is going to be deprecated soon. It will be replaced by b:slider2 when both sliders have the same functionality and when they are compatible. The idea is to use the new component with the old name and to make the old component available with another name for one version.
• net.bootsfaces.legacy_error_classes (since 1.1.0)
• Styles and style-class of b:badge (since 1.1.0)
• b:dateTimePicker: mode="inline" replaced by show-icon and icon-position (since 1.0.2)
• @findIdRecursive(id) may yield more than one id (since 1.0.2)