Add disk space monitoring per user

[jreyesr]

When the app is paid, there will be a limit on available disk space per user (á la Gmail, only 45 GB instead of 15). Therefore, there must be a way to track disk usage per user, display it, and prevent the creation of Flights and Projects when a user is over capacity. Required changes would be:

• [x] Add used_space and maximum_space fields in the User, Flight and UserProject model (probably a PositiveIntegerField) tracking the number of KILObytes (don't track bytes, PositiveIntegerField is only guaranteed to hold a 32-bit integer, which would cap out at 4GB).
• [x] User.maximum_space should have a default value of default=45*1024*1024
• [x] Add a new method update_disk_space(self) on the Flight and UserProject models, that should use something like https://stackoverflow.com/a/1392549 to compute the number of bytes used by the Flight/Project and update the self.used_space field. Don't forget to call self.save()!
• [x] Add a new method update_disk_space(self) on the User model that loops over all UserProjects and Flights that belong to self and updates self.used_space to the new value. Don't forget to call self.save()!
• [x] Add calls to flight.update_disk_space() and flight.user.update_disk_space() on the webhook (after all postprocessing).
• [x] Add calls to proj.update_disk_space() and proj.user.update_disk_space() on the Project creation code path, just after https://github.com/IS-AgroSmart/AgroSmart-Web/blob/8d107206110f10c4276373a7aedd1198d0fcb647/core/serializers.py#L75
• [x] Add calls to flight.update_disk_space(), project.update_disk_space() and proj.user.update_disk_space() after https://github.com/IS-AgroSmart/AgroSmart-Web/blob/8d107206110f10c4276373a7aedd1198d0fcb647/core/views.py#L485-L487 The call to flight.update_disk_space() should be inside the for, the other two calls should go after project._create_index_datastore(clean_index)
• [x] Add calls to project.update_disk_space() and project.user.update_disk_space() somewhere (near the end) on the upload_geotiff and upload_vectorfile views: https://github.com/IS-AgroSmart/AgroSmart-Web/blob/8d107206110f10c4276373a7aedd1198d0fcb647/core/views.py#L406 https://github.com/IS-AgroSmart/AgroSmart-Web/blob/8d107206110f10c4276373a7aedd1198d0fcb647/core/views.py#L355
• [x] Call user.update_disk_space() whenever a Flight or Project is deleted, made demo or made normal again.
  • [x] The delete calls can happen on new post_delete signals, near https://github.com/IS-AgroSmart/AgroSmart-Web/blob/8d107206110f10c4276373a7aedd1198d0fcb647/core/models.py#L466-L467
  • [x] The normal-to-demo and demo-to-normal transitions can be handled on the make_demo and delete_demo actions on the FlightViewSet and UserProjectViewSet classes on views.py.
• [x] On the upload_images view, reject uploads if user disk quota is exceeded: after L236, check flight.user.used_space against flight.user.maximum_space. If over quota, return HTTP status code 402 (Payment Required) https://github.com/IS-AgroSmart/AgroSmart-Web/blob/2849cf12cf783ff0837c91eebeb328c270021382/core/views.py#L232-L238
• [x] On the Flight and Project serializers, add a check on the create method to block creation if user is over quota: get the effective user (can be request.user or User.objects.get(pk=request.META["HTTP_TARGETUSER"])), check the user's used_space and maximum_space; if it's over quota, return HTTP 402.
• [x] Add checks for quota on the create_raster_index, upload_geotiff and upload_vectorfile views. If over quota, return HTTP 402.

[jreyesr]

For the frontend:

• [x] Ensure that the used_space and maximum_space fields in User are exposed by the UserSerializer
• [x] On the frontend, make space somewhere to add the "used space" bar. ~Perhaps to the right of the navbar, near the "My Account" dropdown?~ UPDATE: Placed it on a footer, because the navbar cased alignment issues.
• [x] Use this.loggedInUser.used_space and this.loggedInUser.maximum_space to style a progress bar. Use https://bootstrap-vue.org/docs/components/progress#custom-progress-label to write a nice label. ~Probably use variant="secondary" to contrast with the teal navbar.~
• [x] If this.loggedInUser.used_space >= this.loggedInUser.maximum_space, disable the Create Flight and Create Project buttons. On the AddNewFlightPartial and AddNewProject components:
  • [x] Add a new computed property unable_reason that returns "Póngase en contacto con AgroSmart para activar su cuenta." if this.targetUser.type is not ACTIVE or ADMIN, "Su almacenamiento está lleno." if this.targetUser.used_space >= this.targetUser.maximum_space, and "" otherwise
  • [x] Edit the canCreateFlights/canCreateProjects computed properties to be return this.unable_reason == ""
  • [x] Edit the explanation message to be No puede crear vuelos. {{ unable_reason }} (same for Projects)
• [x] Add a handler for the HTTP 402 status code error on the image upload component, and display a nice error message.
• [x] Add a handler for the HTTP 402 status code error on the index creation, GeoTIFF upload and vector upload fetch/axios calls, and display a nice error message.