Create a set of excel utils to be used for .xls and .xlsx files, for
reading workbook, reading sheets, ... optimize openpyxl access to
sheet to save computation time.
Use this opportunity to refactor service sheet without namedtuple
and simplify code
Signed-off-by: EstherLerouzic <esther.lerouzic@orange.com>
Change-Id: Ibaf3aac40b3f6ca4829d8ea8cd506523d318103a
