[Feat] Hook user language configuration in the language logic

[quantumfate]

As a user/developer I want to be able to inject my language specific settings into the present language algorithms without having to make changes in quantumvim's runtime files.

• factor any settings and conditional parameters in the language section out to a confic file (eventually split logically into pieces such as null-ls, lsp and dap in a modular fashion to support future deprecation)
  • dap
  • null-ls
  • lsp
• provide after and ftplugin folder in the user configuration (NOTE: the runtime path for quantumvim's internal ftplugins has to be placed before the ftplugin folder of the user [Feat] Runtime path modifications and user config after directory #7 )
• update the template generation
• keep documentation up to date