Revert Catalog PSA decisions for 4.13 (Marketplace)

See: https://issues.redhat.com/browse/CPSYN-143

tldr:  Based on the previous direction that 4.12 was going to enforce PSA restricted by default, OLM had to make a few changes because the way we run catalog pods (and we have to run them that way because of how the opm binary worked) was incompatible w/ running restricted.

1) We set openshift-marketplace to enforce restricted (this was our choice, we didn't have to do it, but we did)
2) we updated the opm binary so catalog images using a newer opm binary don't have to run privileged
3) we added a field to catalogsource that allows you to choose whether to run the pod privileged(legacy mode) or restricted.  The default is restricted.  We made that the default so that users running their own catalogs in their own NSes (which would be default PSA enforcing) would be able to be successful w/o needing their NS upgraded to privileged.

Unfortunately this means:
1) legacy catalog images(i.e. using older opm binaries) won't run on 4.12 by default (the catalogsource needs to be modified to specify legacy mode.
2) legacy catalog images cannot be run in the openshift-marketplace NS since that NS does not allow privileged pods.  This means legacy catalogs can't contribute to the global catalog (since catalogs must be in that NS to be in the global catalog).

Before 4.12 ships we need to:
1) remove the PSA restricted label on the openshift-marketplace NS
2) change the catalogsource securitycontextconfig mode default to use "legacy" as the default, not restricted.

This gives catalog authors another release to update to using a newer opm binary that can run restricted, or get their NSes explicitly labeled as privileged (4.12 will not enforce restricted, so in 4.12 using the legacy mode will continue to work)

In 4.13 we will need to revisit what we want the default to be, since at that point catalogs will start breaking if they try to run in legacy mode in most NSes.

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