Fix #634

- Currently, only light export is available, thus export doesn’t contain
  the name of the subscribers. The button solves that.
- The full export always includes a header:
  # Exported subscribers with search filter ""
  But it’s useless and maybe confusing when you use the full export from
  the button. I removed that header if no filter was sent.

WWSympa: TLS client authentication: Now it gets rfc822Name in X.509v3 subjectAltName, otherwise emailAddress attribute in subject DN (the first one of either).

Note: Earlier efforts getting attribute such as MAIL, Email in subject DN are no longer supported.

Replace Sympa::List::load_list_of_scenarios() with Sympa::Scenario::get_scenarios().

This will fix several bugs due to confusion with function and parameter.

[feature] New parameter shared_feature in sympa.conf/robot.conf to enable/disable the feature of shared document repository.

[change] Data sources: outdated users will be expired only when all data sources of the list has succeeded inclusion.
By this change, if there are data sources with nosync_time_ranges set, deletion of outdated users can be delayed 24 hours at most.
[change] Database schema: included_* and include_sources_* in subscriber_table and admin_table were deprecated.  inclusion_* fields will be used instead.

Fixed by getting recent owners/moderators passing cache.

Only from web interface for now.

Fixes:

  - Message footer/header files of domain/site default are put in `mail_tt2` subdirectories while those of list config are not.
    Fixed by put all of them in consistent location without intermediate directories (See also Notes below).
  - Entries for header/footer files in `edit_list.conf` were ignored.

Changes:

  - File names themselves of header/footer were changed:
    `message_header`, `message_header.mime` etc.
    This is due to concideration about conflict between files and directories with domain names (See also Notes below).
  - Header/footer files with `.mime` extension:
    Previously, files with this extension were always preferred, then files without extension were used.  This behavior has not been documented.
    Now files with extension will be searched only in case `footer_type` is `mime`.  Files without extension will be searched in both cases.

Notes:

  - Files with older names/paths in list/domain/site config directories will be copied to new location during upgrading process.
  - Template files with old names in families (`message.header.tt2` etc.) will be used as before and will be copied to new location during instantiation. If files with new names (`message_header.tt2` etc.) will be preferred, if they will be added.

Known bug:

  - There are no web UI to edit global footer (`message_global_footer`).

When user is logged-in, Sympa collects information about membership/adminship among all lists, content of moderation spool and so on, though they will never be used.  Fixed by removing code collectiong information in vain. Deprecated web_tt2/news.tt2.