Thai Localization - Base Sequence

This module refactor the ir.sequence allowing more legends to be added
with minimal code duplication and adding preview fields on both
ir.sequence and ir.sequence.date_range models. the preview field is a
computed fields that only visible in edit-mode of the form view works
with range\_ and range_end\_. It helps users to check and validate the
prefix, suffix, and padding configuration easily without a need to
actually generate an actual document.

Adding more legends to ir.sequence requires an extension of an inner
method \_interpolation_dict() of the \_get_prefix_suffix() method. An
extension of an inner method is impractical, therefore this module
override the \_get_prefix_suffix() method by moving the inner private
method \_interpolation_dict() to a private method. Therefore, this
allows another module to add more legends to the ir.sequence.

This modules works as a base module to other modules to add more legends
to ir.sequence. and extends the ir.sequence allowing range_end\_ ,
range_period\_ and qoy legends. It adds the following legends:

- The end of date_range year with century: %(range_end_year)s
- The end of date_range year without century: %(range_end_y)s
- The end of date_range month: %(range_end_month)s
- The end of date_range day: %(range_end_day)s
- The end of date_range day of the year: %(range_end_doy)s
- The end of date_range week of the year: %(range_end_woy)s
- The end of date_range weekday: %(range_end_weekday)s
- The end of date_range hour in 24-hour: %(range_end_h24)s
- The end of date_range hour in 12-hour: %(range_end_h12)s
- The end of date_range minute: %(range_end_min)s
- The end of date_range second: %(range_end_sec)s
- The period of date_range month: %(range_period_month)s
- Quarter of the Year: %(qoy)s
- The begin of date_range quarter of the Year: %(range_qoy)s
- The end of date_range quarter of the Year: %(range_end_qoy)s
- Current Buddhist Era (BE) year with century: %(year_be)s
- Current Buddhist Era (BE) year without century: %(y_be)s
- The begin of date_range Buddhist Era (BE) year with century:
  %(range_year_be)s
- The begin of date_range Buddhist Era (BE) year without century:
  %(range_y_be)s
- The end of date_range Buddhist Era (BE) year with century:
  %(range_end_year_be)s
- The end of date_range Buddhist Era (BE) year without century:
  %(range_end_y_be)s