19073 allow plugins to be marked as hidden or disabled in plugins table

[arthanson]

Fixes: #19073

Defined a new config parameter PLUGINS_CATALOG_CONFIG, I kept it separate from PLUGINS_CONFIG as those settings are directly controlled by the plugin itself and I didn't want to potentially break it if there were overlap In the names or the plugin wasn't expecting additional params for some reason (probably very unlikely, but...)

PLUGINS_CATALOG_CONFIG = {
    'hidden': ['netbox_acls',],
    'unlinked': ['netbox_bgp',],
}

With this config can see netbox_acls was removed from the list and netbox_bgp is not a clickable link anymore:

In netbox/core/views.py could unfold the if q: lines to make one loop through the list, but thought this was clearer and list comprehension is very fast (and a short list). I also wanted to keep the list with the hidden flags instead of removing them when it initially generates the list as we may potentially want to use the complete list for other things in the future (including hidden items).

        plugins = self.get_cached_plugins(request).values()
        if q:
            plugins = [obj for obj in plugins if q.casefold() in obj.title_short.casefold()]

        plugins = [plugin for plugin in plugins if not plugin.hidden]

[arthanson]

Changed from disabled to unlinked as that seems more descriptive. I think unavailable would also be confusing as it is available / installed it just doesn't have installation instructions or details. Not 100% happy with unlinked

[jeremystretch]

One note: The detail view for a plugin is still visible even if a plugin has been declared hidden or static. It's unclear to me whether this is intended, so I'm approving this as-is.