Add options to config Cachito flags

Use the following options in image metadata config or group config to
control which Cachito flags should be used:

```yaml
cachito:
  enabled: true
  flags:
  - gomod-vendor-check
```

For all valid flags, see https://github.com/containerbuildsystem/cachito#flags

doozerlib/distgit.py

@@ -512,15 +512,28 @@ def _generate_osbs_image_config(self, version: str) -> Dict:
                 pkg_managers = self._detect_package_manangers()
             else:
                 raise ValueError(f"Invalid content.source.pkg_managers config for image {self.name}: {self.config.content.source.pkg_managers}")
+            # Configure Cachito flags
+            # https://github.com/containerbuildsystem/cachito#flags
+            flags = []
+            if isinstance(self.config.cachito.flags, ListModel):
+                flags = self.config.cachito.flags.primitive()
+            elif isinstance(self.runtime.group_config.cachito.flags, ListModel):
+                flags = set(self.runtime.group_config.cachito.flags.primitive())
+                if 'gomod' not in pkg_managers:
+                    # Remove gomod related flags if gomod is not used.
+                    flags -= {"cgo-disable", "gomod-vendor", "gomod-vendor-check"}
+                elif not self.dg_path.joinpath('vendor').is_dir():
+                    # Remove gomod-vendor-check flag if vendor/ is not present when gomod is used
+                    flags -= {"gomod-vendor-check"}
+                flags = list(flags)
+
             remote_source = {
                 'repo': convert_remote_git_to_https(self.actual_source_url),
                 'ref': self.source_full_sha,
                 'pkg_managers': pkg_managers,
             }
-            if 'gomod' in remote_source['pkg_managers']:  # if source is golang
-                # if we have a vendor directory, we will need to add gomod-vendor-check as well: https://github.com/containerbuildsystem/cachito#flags
-                if self.dg_path.joinpath('vendor').is_dir():
-                    remote_source.setdefault('flags', []).append('gomod-vendor-check')
+            if flags:
+                remote_source['flags'] = flags
             config_overrides.update({
                 'remote_sources': [
                     {

tests/test_distgit/test_image_distgit/test_image_distgit.py

@@ -554,7 +554,7 @@ def test_generate_osbs_image_config_with_cachito_enabled(self, is_dir: Mock):
                 "content": {
                     "source": {"git": {"url": "git@example.com:openshift-priv/foo.git", "branch": {"target": "release-4.10"}}}
                 },
-                "cachito": {"enabled": True}
+                "cachito": {"enabled": True, "flags": ["gomod-vendor-check"]}
             },
         }))
         dg = distgit.ImageDistGitRepo(meta, autoclone=False)