* review: Won't process sync_include in advance so that processing will be faster.

* Refactoring. Sympa::List::on_the_fly_sync_include() was removed. Instead, "include" request handler had "delay" option.

* Remove unused "last_sync" cache entries.  "last_change" entries remain.

* sync_include will no longer be invoked during Sympa::List->new():
  - No owner defined in a list is no longer treated as error_config.
  - Instead, if no owner defined,
     - If possible, discard incoming message and send back DSN to original sender,
     - or, notifications to owners will be redirected to listmaster(s).

* Refactoring: Remove unused functions

* Small refactoring: mail_tt2/listeditor_notification.tt2 is no longer used.

* Clarify log messages and DSN about undefined owner/editor/listmaster

* Merge @Sympa::ConfDef::params into %Sympa::ListDef::pinfo
* Merge %Conf::old_params into %Sympa::ListDef::pinfo
* Add aliases of parameter names for compatibility to sympa.conf/robot.conf of earlier versions.
* Move content of Sympa::ListDef to Sympa::Config::Schema
* Move content of Sympa::ConfDef to Sympa::Config::Schema
* Defining additional format entries in config schema.
* Merge sympa.conf(5) and list_config(5) into sympa_config(5).

Instead, the new wwsympa_url_local parameter may be used to specify upstream URL.

  extra-path of script-URI inproperly, we'd be better to reconstruct them:
  SCRIPT_NAME and PATH_INFO.
  Note that we shouldn't use non-standard CGI environment varialbes such as
  REQUEST_URI.
- Additional environment variable SYMPA_DOMAIN stands for available
  mail domain (a.k.a. "robot").
- If no robot providing web service was found according to client's request,
  error response will be returned.

A note:
Now create_list, create_automatic_list & update_automatic_list Request handlers won't take "listname" as an top-level parameter, but it must be included in an item of "parameters" parameter.

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

This change makes session ID by earlier releases incompatible, if Crypt::CipherSaber has been used.

Copying timestamp of original css.tt2 confuses browser cache.  Older timestamp of css.tt2 should be avoided by measures in release and install process.

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`).

Fixed by clearing older style.css* and lang.css* under $CSSDIR when they would be updated.

Note: Among files under $CSSDIR, fullPage.css*, print.css* and print-preview.css* will no longer be used nor updated. These may be removed manuallly.

[change] ldap_authentication() does no longer perform search operations twice, because attributes of user's entry has been retrieved by the first operation.

[change] Deprecate sympa_altemails cookie.  Also, obsolete alternative_email_attribute parameter in ldap paragraph of auth.conf.

Various places in both documentation and default emails to admins/moderators
use he/him/his to refer to generic users of unknown gender. This commit
changes all generic uses of male pronouns to use singular they/them/their.
It also changes "his/her" to "their", but leaves "he or she" unchanged due
to less trivial conjugation issues.  NEWS, AUTHORS.md, and OChangeLog are
unchanged.

Timestamp of css.tt2 is not always increased by new installation.