Issue title: manually (batch) set found state for ZZ and LC caches
 Issue body: @moving-bits ....
Now that the subject capability exists, I believe it makes sense to trigger that function from the top right pull down menu when viewing a list and select mode is turned on and a specific subset of the list entries have been checked. I am not deep enough into the code (yet) otherwise I would give it a try. What makes me hesitate is: what if non ZZ/LC caches are checked in that list, will the set found state method gracefully skip those? What if the operation would be started on the full list not addressing a selected subset but the full list instead? Would it leave non-ZZ / non-LC caches untouched? That would be the rowejames@example.net.
 Comments: 
 Comment 0: I'm not sure if there's really a need to set the found state for several caches at once, but nevertheless here are some info on where to look if you want to implement such a function:

- The menu entry should be added to the "Manage caches" submenu of the caches list menu (see `res/menu/cache_list_options.xml`)
- The action itself is made visible and is triggered from `CacheListActivity` (see `onPrepareOptionsMenu` and `onOptionItemsSelected`)
- the action itself has to be implemented as a `command` (to be revertable), have a look at e. g. `CacheListActivity.deleteCaches(...)`
- within your command you need to check whether the connector for the current cache supports setting the found state (call `supportsSettingFoundState()` on the cache object)

 Comment 1: @moving-bits .... thx for the pointers. As the weather improves I can't promise how much time I can put into it but I will keep it on the stack. I treat it as a WBNI (wouldn't it be nice if ....)

A related issue: I just noticed on my own build (which includes my yesterday's merged PR), that ALCs marked as "found" are not excluded on the map if "Own/found" is unchecked in the map's quick settings. All other types are excluded as expected. In what area of the code would I look for this aspect?
{'source': 'GithubIssues', 'repo_name_with_owner': 'cgeo/cgeo', 'issue_id': 877281034, 'repo_stars': 1233.0}