WIP - Please cherry-pick:

WIP - Please cherry-pick:
- started proting to PrimeFaces 6.0
- PF theme "bootstrap" is now the theme
- mobile provider list in admin area should be now ported
- removed many own CSS as it conflicted with jQuery UI, still tons of to go
- added more i18n strings for empty lists
- replaced all h:commandButton -> p:commandButton
- replaced all h:link -> p:link
- admin menu is now rewritten in PF (still looking a little messy)
- replaced h:dataTable -> p:dataTable and also h:column -> p:column (belongs
  together)
- widgets:outputMessageBox is no longer needed as p:dataTable has "emptyMessage"
  attribute for this
- if you have p:dataExporter, also use p:commandButton
- added missing admin_country_links.tpl (custom JSF tag)
- replaced h:message[s] -> p:message[p]
- finally found a way of getting rid of project name in base.tpl, thanks to the
  people at stackoverflow
- widgets:outputMessageBox now accepts common "id", was required for "for"
  attribute
- f:view seem to be self-closing?
- added f:facet and more meta tags for upcoming responsive
- used a bit pm (PF mobile)
- now will use p:growl instead of main h:messages in base.tpl
- also added AJAX exception handler and p:dialog (does it work?)
- everthing else I oversaw/forgot

Signed-off-by: Roland Häder <roland@mxchange.org>