Added new features

[sb0r]

• new data_type "qgis_project_layer", i.e. the user can now search
  in any vector layer in the QGIS project.
• natural sorting of search results (important for address searches)
  included the python-natsort package
• new search flags "Comparison Mode" and "Toggle Case Sensitivity"
• user control when autocompletion starts
• German translation

So far, the new features work only for the gpkg and qgis_project_layer
data_types but I could also add them to postgres and mssql, if you like.

[saberraz]

Hi @sb0r ...that is great! thanks a lot for your PR...some very cool features.

To review and comment, it will be easier to have one PR for each feature. So, would it be possible to break-down your PR to multiple ones for each feature?

[saberraz]

@sb0r no worries for splitting it to multiple PRs for this one.