Extract project dictionary from `cSpell.json` config file

[josecelano]

Instead of adding an accepted word in the cSpell.json config file, use an independent dictionary like in the Index.

https://github.com/torrust/torrust-index/blob/develop/cspell.json

{
  "$schema": "https://raw.githubusercontent.com/streetsidesoftware/cspell/main/cspell.schema.json",
  "version": "0.2",
  "dictionaryDefinitions": [
    {
      "name": "project-words",
      "path": "./project-words.txt",
      "addWords": true
    }
  ],
  "dictionaries": ["project-words"],
  "ignorePaths": ["target", "/project-words.txt"]
}