fix(report): unify .rst section marks

Unify characters marking section levels,
(at least for methodology Vratko contributed to):

Level 0: ==== Do not use, or use for index.rst only.
 (Because git conflicts also create ====.)
Level 1: ^^^^
Level 2: ~~~~
Level 3: ````
Level 4: ____
Level 5: ---- Do not use.
 (Because other documents use this as level 0,
 and it also appears in tables.)

Change-Id: I10813f718b2ee34d1e34c58e62e88353000340e9
Signed-off-by: Vratko Polak <vrpolak@cisco.com>