Check available disk space before downloading/extracting images

[MatteoPologruto]

The arduino-flasher-cli should do the following:

• allow the user to specify, using a flag (for example --temp-dir), a different directory to download and/or extract the image. $HOME/.cache might not be big enough if the user has multiple hard disks.
• check if there is enough free disk space where the image is going to be downloaded and extracted, before taking any other action. Warn the user and exit if the space is not enough.

Additional context

Related

• Don't download to tmpfs #21
• Arduino Q: arduino-flasher-cli could use a few improvements #20

[HeadBoffin]

Given that I now have 11.4GB of files added to my computer, this could be defined as exceptionally urgent with a side order of "do you need some help with figuring out what's normal for other development eco-systems"

I've found the file(s) on MacOS now "~/Library/Cache/arduino-flasher-cli" so I can save the file for a reattempt at running the update as it lost the connection to the board during the unexpectedly large download.

Downloading many separate parts so that resume is simpler and unpack as it goes rather than having the update.tar.zst at 2.32GB plus the 9.11GB it unpacks to would be nice.

The compression ratio implies lots of empty space - maybe the flasher could unpack on the fly?

These words may seem a bit blunt, but these sorts of deliverables don't bode well for a new platform given the resources available to the company.

[HeadBoffin]

OMG, it cleared the cache when it fell over. Cache is for keeping local copies. It is NOT for temporary files. Meh