TektonInstallerSet created have each resource twice

[sm43]

When we read resources from ko data and create installer set, the installer set has 2 copies of each resource.

for eg,
In addons, for clustertasks, when we read clustertasks from kodata here -> it calls applyAddons
in apply addon we pass the path of the directory to common.AppendManifest(manifest, addonLocation) and it
reads all the resources at the location and returns inside the manifest obj
but the manifest has 2 copies of each resource so manifest is getting bigger.

It is probably issue with AppendManifest

To reproduce the issue

1. install operator using make TARGET=openshfit apply` on Openshift
2. let all profile install all components
3. for addons there would 4 installler set created
4. check any installer set if there are 2 instances of each resource eg. in clustertask addon-clustertask- installerset there would be 2 buildah clustertask which are same.

[sm43]

/assign