We are incorrectly using formData in a get request. To move
away from this we send both query params and formData until
the server is fully upgraded. After which we can stop sending
formData.
Additionally, write some tests to ensure the driver method
`startBlacksmithBuilder` handles all exceptions correctly in
both nofallback=true and nofallback=false configurations.
This change teaches the build push action to request a stickydisk
every time it runs. Once the SD is hotloaded the VM will mount
the buildkit root dir and starts buildkitd.
1. Checks we have buildx installed
2. Configures a remote builder if we get an address back
3. Uses the already configured builder if we don't get an address back
This change does not plumb the dockerfile path through as the entity,
and does not differentiate a failed build from a succesful to report
to anvil in the post step yet.
