fix: argument must be of type OutputProviderInterface

See merge request !167

Changed the variable name `$OutputProvider` to `$outputProvider` to adhere to camelCase naming
standards. Also moved the instantiation of `$outputProvider` inside an if block to prevent
unnecessary instantiation when `$outputProvider` is empty.

Related: pcsg/kunden/libellio/b2c/core#196

fix(Process):  getGroupedRelatedTransactionEntities checks invoices correctly

See merge request !166

Related: pcsg/buero#491

fix(ArticleListUnique): no longer format already formatted totals

See merge request !165

fix: html to pdf document -> has erp entity

See merge request !164

fix: check const defined at pdf download

See merge request !163

Next 3.x

See merge request !162

fix: check vat -> wrong quantity calc check

See merge request !161

fix: declaration of ArticleList::toHTMLWithCSS must be compatible with...

See merge request !160

fix: declaration of ArticleList::toHTMLWithCSS must be compatible with ArticleListUnique::toHTMLWithCSS

feat(ArticleListUnique): toHTML() can be passed to template engine and thus...

See merge request !159

feat(ArticleListUnique): toHTML() can be passed to template engine and thus settings / variables can be passed on

Related: order-simple-checkout#12

fix: erp pdf view - all pages

See merge request !158

feat: pdf viewer via pdf.js

See merge request !157

Related: #105

fix: pdf preview check

See merge request !156

Related: #105

fix: pdf view is available for every view and is memorized

See merge request !155

feat: pdf preview in the print dialog

See merge request !154

Related: #105

fix(Send ERP Mail): uncaught error: call to a member function getMedia() on null

See merge request !153

fix: correctly check if translation of unit exists

See merge request !152

Related: #104

fix: correctly check if translation of unit exists

See merge request !151

(cherry picked from commit 21a31f8f)

Co-authored-by: Patrick Müller <p.mueller@pcsg.de>

Next 3.x

See merge request !150