Allow disabling inheriting ExcludeArch to noarch packages

Copying ExcludeArch/ExclusiveArch from source rpm to noarch is an easy
option to block shipping that particular noarch package from a certain
architecture. However, there is no way to bypass it, and it is rather
confusing and not discoverable.

An alternative way to remove an unwanted package is to use the good old
`filter_packages`, which has enough granularity to remove pretty much
anything from anywhere. The only downside is that it requires a change
in configuration, so it can't be done by a packager directly from a spec
file.

When we decide to break backwards compatibility, this option should be
removed and the entire ExcludeArch/ExclusiveArch inheritance removed
completely.

JIRA: ENGCMP-2606
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/checks.py

@@ -830,6 +830,10 @@ def make_schema():
                 "type": "boolean",
                 "default": True,
             },
+            "pkgset_inherit_exclusive_arch_to_noarch": {
+                "type": "boolean",
+                "default": True,
+            },
             "pkgset_scratch_modules": {
                 "type": "object",
                 "patternProperties": {