Foreman » Smart Proxy

Fixes #37147 - Pass --fail option to curl

This prevents curl from writing out error pages, for example when the
URL returns a HTTP 404.

It still doesn't return any error to Foreman since the TFTP
/fetch_boot_file only starts a thread and there's no way to monitor it....

Fixes #34163 - Allow clearing the log buffer

In testing it can be useful to reset the log buffer. This is not
intended to be used as a public API but tests can use:

Proxy::LogBuffer::Buffer.instance.send(:clear)

refs #36243 - Templates - Return Foreman's API status code

Bugfixes and improvements

refs 70073c07e991cbe85a332a00e90d4196d8cbcaaf

Fixes #36243 - Templates - Return Foreman's API status code instead of 500

Fixes #36209 - tftp initrd/vmlinux generation: curl malformed

PR #856 was fixing invalid curl --time-cont condition,
but it actually break it and now files are not downloaded at all.

This reverts commit fba49ab1eb9bbe383572575309558ff628f5de60.

Fixes #36138 - Invalid syntax for curl --time-cond

According to Curl man page, syntax for --time-cond attribute
should be "--time-cond file <path>", not "--time-cond <path>".

This can cause issues with outdated vmlinuz and initrd.im files,
once the files are downloaded, they are never replaced with never versions....

Fixes #35921 - Disable access logging for https endpoint

Previously, access logging was enabled for https endpoint, but not for
the http one. This commit settles things on no access logging for both.

Refs #35921 - Unify use of common app settings

Common options were previously duplicated between http and https
application settings.

Refs #35639 - Add OptionalUrl validator

Fixes #31118 - Remove daemonize support

Currently Smart Proxy is able to daemonize and manage a pid file.
However, in the common deployments under systemd and Windows this isn't
actually used. There are also other solutions out there to manage it
externally if it's needed....