Case-insensitive search, filtering and sorting

[thomaslow]

Related issues:

• Fixes Sort project titles case-insensitive #3295
• Fixes Extended Search: option to ignore upper and lower case  #4980

This pull request changes the ElasticSearch mapping such that certain information is stored in lower-case form, which allows for case-insensitive search, filtering and sorting.

The following fields are changed to case-insensitivity by this pull request:

• process.title
• process.project.title
• process.comments.message (the combination of all comment texts for a process)
• task.title (e.g. Scanning, QC)
• task.processForTask.title

Additional process meta data in "mdWrap.xmlData.kitodo.metadata.[something]" is already searched case-insensitive.

Example: You can case-insensitive search for a process title now:

Example: You can case-insensitive search for tasks in certain steps:

Example: You can case-insensitive sort process titles now:

[oliver-stoehr]

I only found a small typo in TaskServiceIT.java:262.
Apart from that everything looks good and works as intended.