Removed sections that require major rework to fix incorrect guidance.

In addition to the below, This commit also moves the landmark section after the example section.

Moved each of the following sections from aria-practices.html to aria-practices-DeletedSectionsArchive.html
and created associated issues for drafting new versions.
1. Section "General Steps for Building an Accessible Widget with WAI-ARIA" and created issue #73.
2. Section "Other Widget Authoring Practices"., primarily about aria-valuenow, there is no specific need to raise an issue for this section.
3. Section "Relationships" and raised issues #74, #75, #76, and #77.
4. Section "Managing Dynamic Changes" and created issue #78.
5. Section "Presentation Role" and created issue #79.
6. Section "Form Properties" and created issue #80.
7. Section "Drag-and-Drop Support" and created issue #81
8. Section "Math" and created issue #82.
9. Section "Reusable Component Libraries" and created issue #83.
10. The following 4 Appendix sections related to background on ARIA and created issue #84
A. Background on WAI-ARIA
B. Filling the Gaps for Content Delivered to Desktop Browsers
c. Building Accessible Applications with WAI-ARIA
D. Reasons for Adopting WAI-ARIA
11. The following design patterns:
A. Accordion and updated issue #53.
B. Autocomplete and updated issue #31.
C. Combobox and updated issue #31.
D. Datepicker and updated issue #57
E. Dialog (Non-Modal) and updated issue 59.
F. Dialog (Tooltip) and added issue #85.
G. Landmarks and added issue #86.
H. Popup Help (aka Bubble Help) and added issue #87.
I. Rich Text Editor and added issue #88.
j. Site Navigator - General and added issue #89.
K. Site Navigator - Tree and added it to issue #89.
L. Site Navigator - Tabbed Style and added it to issue #89.
M. Tree Grid and added issue #91.
N. Wizard and added issue #92.