Add the "install the Composer client" link to the install tool
Fix the link button padding (`a.tl_submit`)
Hide buttons in the install tool if they are not required anymore (see #6988)
Correctly generate absolute URIs in `Controller::generateFrontendUrl()`
Update the language files
Do not use `date_default_timezone_get()` in the configuration file (see #6989)
Make sure the security questions gets always generated (see #6990)