allow html and pdf export customization with twig templates

[kevinpapst]

Description

• adds new directory var/export/ where *.html.twig and *.pdf.twig can be placed for simple adding of new HTML and PDF exports
• added new PDF template, which includes remaining project budget
• added remaining project budget to project summary in html export

TODO

• documentation!

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 kimai: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 #1582 into master will increase coverage by 0.04%.
The diff coverage is 98.51%.

@@             Coverage Diff              @@
##             master    #1582      +/-   ##
============================================
+ Coverage     92.03%   92.08%   +0.04%     
- Complexity     4673     4701      +28     
============================================
  Files           436      438       +2     
  Lines         14435    14550     +115     
============================================
+ Hits          13285    13398     +113     
- Misses         1150     1152       +2     

Impacted Files	Coverage Δ	Complexity Δ
src/Export/Renderer/HtmlRenderer.php	100.00% <ø> (ø)	2.00 <0.00> (ø)
src/Export/Renderer/PDFRenderer.php	100.00% <ø> (ø)	2.00 <0.00> (ø)
src/Repository/ProjectRepository.php	93.49% <80.00%> (-0.65%)	50.00 <7.00> (+4.00)	⬇️
src/DependencyInjection/AppExtension.php	93.22% <100.00%> (+0.17%)	38.00 <0.00> (ø)
...cyInjection/Compiler/ExportServiceCompilerPass.php	100.00% <100.00%> (ø)	7.00 <0.00> (+4.00)
...encyInjection/Compiler/TwigContextCompilerPass.php	100.00% <100.00%> (ø)	5.00 <0.00> (+1.00)
src/DependencyInjection/Configuration.php	98.44% <100.00%> (+0.04%)	29.00 <1.00> (+1.00)
src/Export/Base/HtmlRenderer.php	97.91% <100.00%> (+0.61%)	10.00 <4.00> (+3.00)
src/Export/Base/PDFRenderer.php	94.59% <100.00%> (+1.73%)	9.00 <3.00> (+2.00)
src/Export/Base/RendererTrait.php	98.46% <100.00%> (+0.84%)	16.00 <9.00> (+9.00)
... and 5 more