[FEATURE] Create projects

[Androz2091]

Is your feature request related to a problem? Please describe.
I'm always frustrated when I see I can only edit only the files at my root folder... And there is no app like this one.

Describe the solution you'd like
It would be nice to be able to Create a project instead of only opening a folder. We could configure our project, and add files filter like on Crowdin:

It will fix #368. We could export our project configuration to a JSON file and publish this file on our Github repo. Like:

{
    "sourceLanguage": "en-US",
    "targetLanguages": [ "fr-FR" ],
    "filesToTranslate": [
          {
               "source": "./i18n/en-US/core/*.json",
               "target": "./i18n/%lang%/core/%file%.json",
          },
          {
               "source": "./i18n/en-US/*.json",
               "target": "./i18n/%lang%/%file%.json"
          }
    ]
}

And on the project window, we have the languages with the % of strings that are translated.

Describe alternatives you've considered
At least it would be great to be able to edit files in subdirectories (#368). Many projects use this structuration (https://github.com/sylkellc/typicalbot/tree/3.x/etc/languages for example).

[gilmarsquinelato]

Hey @Androz2091
I didn't forget your last issue about the support for your structure
I didn't have time yet to analyse it, and as I said, if it will be possible, I'll release it in v3.1
So we don't have to create projects