kconfig: assert: Introduce kconfig option ASSERT_NO_FILE_INFO

Default behavior is to include __FILE__ info with all of the Zephyr
assert macros, __ASSERT, __ASSERT_NO_MSG and __ASSERT_LOC. Setting the
ASSERT_NO_FILE_INFO kconfig option, replaces the __FILE__ with an
empty string, thus removing the file information from the asserts.

The intention here is to allow for code space limited devices to run
with asserts enabled.

Signed-off-by: Danny Oerndrup <daor@demant.com>