[docker] Finish dockerizing the project

[csidirop]

• Add links to Impressum und Datenschutzerklärung in main page
• Add links to Impressum und Datenschutzerklärung in viewer
• Move all variable code to its own files
• Update all branches for the future
• Update Readmes
• Update Readmes: Add and describe environment vars & add maybe more Docker commands (see SLUB)?
• Add global support for UTF8
• Better differentiation of image versions: Add date to image-tag
• [Optional] Use some less hacky ways of implementing some features
• ...

[csidirop]

• Move all variable code to its own files:

• Move AdditionalConfiguration.php from entryscript out: 4322cd7

• Move config.yaml from entryscript out to data/: fc7813b

• Move Text and Code from entrypoint to external file: d3b4248

[csidirop]

• Update all branches for the future:

• main: 8b64755

• dfgviewer-5.3: 06c7f74

• presentation-v3: 06d93cd

• presentation-v4: 47c82be

[csidirop]

• Update Readme: 7b90a70

[csidirop]

• Add global support for UTF8: 300357e csidirop/typo3-docker@aa2e4ff e173c68

[csidirop]

• Better differentiation of image versions: Add date to image-tag: 1365e3e