Fix #13163: Remove limitation on password length with MD5 authentication

A new function auth_get_password_max_size was added in authentication_api.php,
to return the maximum length of the password, taking the login method into
consideration: limited to the database field size (PASSLEN) for PLAIN and
BASIC_AUTH, or to new constant MAX_PASSWORD_SIZE for other, hash-based methods.

The return value is used to define the maxlength attribute of all the password
fields.

This commit is a manual port to master of the changes in commits 4664aebf,
9c7fffbb, 5d527ef4 and b2c1c1e9
Renaming the db field length constants

USERLEN ==> DB_FIELD_SIZE_USERNAME
REALLEN ==> DB_FIELD_SIZE_REALNAME
PASSLEN ==> DB_FIELD_SIZE_PASSWORD
Documentation update following #13163

Updated documentation about the password length limitation.

Modified layout slightly and made it more obvious that some authentication
methods are deprecated; changed some wording.

Updated comment in config_defaults_inc.php about possibility
to change $g_login_method at will, to reflect documentation
(and reality).
Complete rewrite of LDAP authentication section in Admin guide

The information in this section did not really provide useful information to
the administrator
Fix #13171: Resetting columns config in My Account asks for reauthentication

Since this is an end-user function, reauthentication should not be required
Updated CREDITS with current dev team
Fix #11282: Oracle error ORA-00918 column ambiguously defined

Filter API does a SELECT DISTINCT $t_bug_table.*; before this patch the fields
list also included 2 additional columns; MySQL had no problem with that, but
Oracle gave the above-mentioned error.
Bugnote API: allow skipping of history event logging when adding notes

Affects #13167: Clone task: allow copying of notes
Extract attachment copy logic into file_copy_attachments

Affects #13166 : Clone task: allow copying of attachments
Bug cloning: allow copying of notes and attachments from parent bug

Fixes #13167 : Clone task: allow copying of notes
Fixes #10367 : Moving attachments while cloning issue
12759: Error loading language string when plugin is not current

Signed-off-by: Damien Regad <damien.regad@merckgroup.com>
Fixes #13190: View page doesn't honor view_handler_threshold threshold.

The issue handler shows up in the following areas:
- The 'assigned to' field.
- The issue history.
Fix #13192 : Gracefully handle empty return for hook EVENT_MENU_FILTER
Fix #13193 : Files served by plugins do not have a Content-Type header set

Conflicts:
	config_defaults_inc.php
Fixes #13190: View page doesn't honor view_handler_threshold threshold.

- Follow fix to add missing parameter in API call.
Fix #13225: Inconsistent handling of project file upload path

Create a new function in project api to handle the file path validation and
move the code comparing project file path check vs default path currently in
manage_proj_create.php into the new function.

The function is called from both project_create and project_update to ensure
consistent behavior.
Fix #13226: Installation check should verify that default file upload path has trailing /

Add config option absolute_path_default_upload_folder to the list of paths to
validate in check_paths_inc.php
Verify that file upload path is writable in installation check
Fix #11458: Missing attachments can not be deleted
Fix #13228: SQL error in bugnote_api.php with PostgreSQL

ERROR: column "u.realname" must appear in the GROUP BY clause or be used in an
aggregate function

Bug was introduced in release 1.2.6, commit c4c0a01e1f715aea775a36d3a6c7bc8bd74b5b8b.
A new column was added to 2 SQL statements' SELECT clause, but the GROUP BY
was not updated to match.

This passed testing, as MySQL is more (too?) permissive and allows the SELECT
clause to refer to ungrouped columns that are not in aggregate functions.

This commit also removes unnecessary "u.id" column from the group by clause.