Backport HSTCONFIGEDIT-120: ":" can not be used as a sitemenu character

This issue is actually fixed as part of HSTCONFIGEDIT-120, but it worked fine only in trunk, not in branch. So cloned this one from the original.

--------------------------------------------------------------------------------------
It's not possible to have a ':' sign in the site menu (also not in URL's, but that make sense).
Reproduction path for This is tested in Go Green Demo CMS 7.8.0
This was also reported for 7.7, so a backport is also requested

route to follow to change a menu item:
(This works!)
-Log in the CMS and go to the channel manager and choose the dutch website
-Click on 'wijzig channel'
-Click on 'URL & navigation management' (on the right, in the 'gear icon')
-Click on 'site menu'
-Click on 'Over Ons' (just used for this example)
-Change the content in the field 'Naam' from 'Over Ons' to 'Just testing'
-Click on 'bewaar'
-Go back to the dutch website
-click on 'sla op & sluit'
-Click on 'publish channel'
-Menu item should be changed now.

Now with the ':' in the menu:
(this doesn't work!)
-Log in the CMS and go to the channel manager and choose the dutch website
-Click on 'wijzig channel'
-Click on 'URL & navigation management' (on the right, in the 'gear icon')
-Click on 'site menu'
-Click on 'Over Ons' (just used for this example)
-Change the content in the field 'Naam' from 'Over Ons' to 'Over: ons'
-Click on 'bewaar'

At this point you'll see that you've got the confirmation that the change is made. However, the folder name in the menu is not changed. (see screen-1). This is the case in the first example. (see screen-2)
When I save take the last 4 steps in the first example, the change also doesn't appear on the website.

This is tested in Go Green Demo CMS 7.8.0

Regards,
Tom