gitweb: fix mobile page overflow across log/commit/blob/diff views

gitweb: fix mobile page overflow across log/commit/blob/diff views

On mobile-sized viewports, gitweb pages in log/commit/blob/diff views can
overflow horizontally due to desktop-oriented paddings and fixed-width
preformatted content.

Extend the existing mobile media query to rebalance those layouts: reduce
or clear paddings in log/commit sections, and allow horizontal scrolling
for preformatted blob/diff content instead of forcing page-wide overflow.

All layout adjustments in this patch are mobile-scoped, except one global
safeguard: set overflow-wrap:anywhere on div.log_body. Log content can
contain escaped or non-breaking text that behaves like a single long token
and can overflow at any viewport width, including desktop.

Signed-off-by: Rito Rhymes <rito@ritovision.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>