Improvements in the database setup documentation

Move the first sentence out of the H2 subsection to directly under
the section header.  This is an introduction that is relevant to
the whole section, not only H2.

Split the H2 subsection into paragraphs, and reword the first
paragraph a bit, to make it a bit easier to read.

Change-Id: If4db63dc3c2a405726edfb1ae939cd852309c07a
1 file changed