Support numeric values for channel parameters/settings

From client project:

When working with the channel parameters / settings we noted the numeric values short, int, long + corresponding wrappers are not supported. In the documentation [1] section "Component Parameters and Channel Parameters" shows `short, int, long, java.lang.Short, java.lang.Integer, java.lang.Long - Text field that accepts only numeric values`, where somewhere more to the bottom of the page a note is placed "Only channel properties of type String and boolean are supported."

To me as a developer it seems quite unclear whether that last note is only about the channel parameter help texts or also about the supported field types. To further improve the CM I think an improvement should me made to "fix" the numeric fields for CM parameters. As in some cases they can be quite handy

Steps to reproduce:

1. Create a custom ChannelInfo interface, and configure it as a hst:channelinfoclass parameter
2. Add a method with a numeric return type (short / int / long)
3. Try editing & saving the numeric fields through the channel parameters UI, they are not getting saved.

[1] https://www.onehippo.org/library/concepts/template-composer/annotate-channel-or-component-configuration-parameters-with-ui-directives.html