Small changes for additional workflow

[atl285]

Is your feature request related to a problem? Please describe.
Yes, I have a manual workflow, because my Bambu Lab printer doesn't support Spoolman directly. But I use Spoolman to track my filaments. So my current workflow is, to measure the weight of the spool after usage and then to enter the current weight into the database (via command line api call using curl). From my scale I get the weight of the reaming filament including the spool weight. But I can‘t enter it directly into Spoolman (web interface).

Describe the solution you'd like
To get this workflow smooth and easy, only 2 things are missing:

1. Add the ability to enter the current spool weight (including spool) as optional input to the "Adjust Spool Filament" dialog.
   

2. Add a button for the "Adjust Spool Filament" dialog to the "spool show" page, so that this can be changed there directly.
   

What's the benefit? Now it is possible to scan the label from the spool via mobile phone and enter directly the current weight. This creates an easy and smooth workflow for users to track their filaments even if they don't have any supported printer.

[lightmaster]

I'd love to see the Adjust Spool Filament popup updated with a Measured Weight option (that's the name that is also used on the Edit Spool tab). This seems like a logical extension of #63.

[atl285]

As an alternative It would be help to add an "update" button to the spool page. The API call for this function does already exists. But I have no knowledge in programming with React. 😞