Restyle the send reminder form

Fixes #17832

Signed-off-by: Victor Boctor <victor@mantishub.net>
Re-style search label in Manage User page

Fixes #17815

Signed-off-by: Victor Boctor <victor@mantishub.net>
Fix #17912: display of "\n" in summary submenu

Regression introduced by 0552366c6e2aff04efd4d3ada7c794b6300bb8f5.
Add support DejaVu Font http://dejavu-fonts.org/ for MantisBT Graph plugin
DejaVu font support when using JpGraph library
Whitespace and coding guidelines
Improve get_font_path() to handle DejaVu fonts

On most Linux systems, the DejaVu font is installed by default whereas
the MS TrueType fonts may not.

The function now checks for 'dejavu' directory below the base font path
prior to checking the 'msttcorefonts'. This gives a better chance to
have a valid fonts directory when $g_system_font_folder is not defined.
Resize synthese.gif to 16x16 pixels

Required so that the graph api's submenu elements in summary page are
all aligned vertically.
Renaming summary graph page

Make the name consistent with other graph pages
Improve layout of icons in menu items

Added new CSS with right padding on images to have a small gap between
the icon and the menu text
Improve code to generate plugin's submenus
Whitespace
Align submenus with core summary page
Fix graph X axis display
Add category to relationship graph's tooltip
Graph plugin: HTML/CSS for config page

Refactor HTML to use form-container class for alternate rows.
require_lib() now accepts optional path

This allows callers to specify an alternate path to $g_library_path.
Useful e.g. for plugins relying on 3rd-party libraries not located in
the same place as other MantisBT libraries.
Graph: use require_lib() to include jpgraph
Fix left margin for graphs by date

The margin was slightly too small, causing axis labels to be cut off, as
well as the leftmost date.
Use plugin_require_api() to include Period.php

Prior to this, the graphs would not render due to a SYSTEM WARNING:
'require_once(Period.php): failed to open stream: No such file or
directory'.

Fixes #17521