odt_style: Fix hierarchy of ReportSection(title=)

When using report sections with title, this is supposed to create outline
in PDF, but this seem to became broken somewhere in the last 10 years.

This repair by using text:h instead of text:p and by setting
text:outline-level
8 jobs for for_testrunner_2 in 0 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner2

01:54:01

running ERP5.CodingStyleTest-TestRunner2

28299:19:56

failed ERP5.UnitTest-TestRunner2

03:55:41

running ERP5.UnitTest-TestRunner2

28299:20:05

failed ERP5.CodingStyleTest-TestRunner2

01:57:35

passed ERP5.CodingStyleTest-TestRunner2

02:37:50

failed ERP5.UnitTest-TestRunner2

03:22:38

passed ERP5.UnitTest-TestRunner2

03:43:22