Install: fix layout of check and options sections

Incorrect closing of tables and divs within the various conditional
blocks caused the title of the 'Installation Options' section to be
displayed as a "sub-table" under the 'Checking Installation' section,
followed by the actual install checks and finally the list of
installation options.

This commit moves the closing tags as appropriate, so that

• checks are listed as a table under 'Checking Installation' section
• 'Installation Options' is displayed as an independent section below
  the checks

Fixes 0022850