Add LimitRequestBody configuration for Horizon

Since CVE-2022-29404 is fixed [1,2] the default value for the
LimitRequestBody directive in the Apache HTTP Server has been changed
from 0 (unlimited) to 1 GiB. This limits the size of images (for
example) uploaded in Horizon. This change add the ability to
configure the limit.

1. https://access.redhat.com/articles/6975397
2. https://ubuntu.com/security/CVE-2022-29404



Closes-Bug: #2012588
Change-Id: I4cd9dd088cbcf38ff6f8d188ebcc56be7d9ea1c9
Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com>