[WIP] Enhance slr feature

[DominikVoigt]

The goal of this PR is to improve the SLR feature.
Most of it based on: https://discourse.jabref.org/t/systematic-review-tool-feedback/2791

Current todos

• Remove search date from config file
• Make use of lower case name for fetchers in config file/repository structure without killing persistence
• Enable the usage of library-specific query refinements in the config file and model <- Before this, test creating a new SLR and continuing an existing SLR
• Rename library-specific query refinements to refinements
• Use raw query string for fetchers (internally)
  • Add ADR: fetcher use raw data (this) OR fetcher use transformers
  • Fetchers get passed the query string from transformers or get the raw query passed through
  • transformers have to be found automatically <- Implement WebFetchers to provide the correct transformer for each fetcher

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• Provide fetchers these refined queries raw
• Add UI for this extendable queries idea
• Add modification UI for SLR definition
• add option in UI to use "lax mode" (allow raw queries)

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• Provide a tutorial for the process and differences between strict and lax mode
  • Extend the pool of translatable query languages

Additional topics

• Add checking for parseable/transformable queries
• Add methods for fetching that signal (Mainly used for UI):
  • whether the query could be transformed or was passed plain
  • whether an id fetcher was used instead -> introduce the corresponding layer between fetchers and UI/SLR