Resolve "voucher should have optional activy type (free text)"

Every voucher has optional field: activity type (free text).

This field if set should be considered as part of the voucher type.

Closes #223 (closed)

added 10 commits

• f6b7dfe5 - debug print removed
• 4d524b21 - adding worker with password mismatch doesn't crash system anymore
• a03b7d85 - data inside table cells are modified by templates
• 77728535 - number is shortened by one digit
• a042a82b - voucher partner code comes befor voucher type code in the voucher number
• 50714faa - voucher contains activity_type field
• 4f56c348 - activity_type is disabled when editing voucher
• 25fc7b14 - activity_type is part of voucher type
• 9b868369 - activity_type is included on printable voucher
• 0302719f - unit test for checking voucher template replacements

Compare with previous version

unmarked as a Work In Progress

changed the description

assigned to @valentin.groues

mentioned in commit c0070e26

merged