Localisation updates from http://translatewiki.net.
Do not display login dialog when using HTTP_AUTH

Fixes #11084
Revert "Do not display login dialog when using HTTP_AUTH"

This reverts commit 90633ab8bcfd1b9f42ad8a1882f6b1b26716cec5.
Localisation updates from http://translatewiki.net.
Documentation: revised Makefile

Fixed the following issues:

- 'all' rule now actually builds all targets
- 'html.tar.gz' was not doing anything
- 'install' rule simplified using a foreach function on a list of
  file extensions to copy
- added tar.gz to list of extensions to copy during 'install'
- updated help text