Sort out the bitcoin-disk partition situation on lizard

Originally created by @intrigeri on #13177 (Redmine)

It’s been in WARNING state since June 21 => assigning to the sysadmin on duty back then. We’re far from having allocated everything planned for this partition, so we could grow it a bit as a temporary fix. But a real solution is needed, and we don’t have enough space available to grow this partition as much as we planned, due to the Vagrant thing having been deployed and tails/tails#12002 not being done yet.

Related issues

• Related to tails/tails#12002
• Related to tails/sysadmin#13583
• Blocks tails/sysadmin#13232