customer-name as part of the invoice number

[kevinpapst]

Description

allow to use customer-name and customer-number as part of the invoice number

See #2636

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I verified that my code applies to the guidelines (composer code-check)
• I updated the documentation (see here)
• I agree that this code is used in Kimai and will be published under the MIT license

[codecov]

Codecov Report

Merging #2640 (3f6613b) into master (6d19687) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master    #2640   +/-   ##
=========================================
  Coverage     92.61%   92.62%           
- Complexity     7007     7009    +2     
=========================================
  Files           639      639           
  Lines         20887    20893    +6     
=========================================
+ Hits          19345    19352    +7     
+ Misses         1542     1541    -1     

Impacted Files	Coverage Δ
...ce/NumberGenerator/ConfigurableNumberGenerator.php	98.05% <100.00%> (+0.12%)	⬆️
src/Repository/TimesheetRepository.php	89.44% <0.00%> (+0.17%)	⬆️