Working end-to-end measurement verification

[alexhulbert]

Best reviewed per-commit.

This PR primarily consists of me using lower level strategies for getting platform metadata, since the strategies I was using prior to this PR were flaky for certain GCP instance sizes (and image sizes) and didn't work properly across cloud providers.

I also added some quality of life improvements like a debug switch in the verify cli and encoding the quotes as base64 strings.

Fixes for RTMR0:

• Detect platform directly from DMI rather than systemd
• Read memory size directly from SMBIOS
• Correctly reports the number of attached external disks on all platforms

Fixes for RTMR1:

• Fixed GCP tar.gz ESP size calculation for mkosi images under 260MiB

[alexhulbert]

@bakhtin This should work now on GCP. Let me know if you're still having problems. You'll have to apply these changes to your mkosi gcp postoutput file:

flashbots/flashbots-images@63c4f20#diff-e3ab5efb8991876f7311dfd1f63cc43f9ddbae6abf3af2801cd78b84a2c45269R10-L20

flashbots/flashbots-images@63c4f20#diff-3b2385261591af5f608af20da1d4f4fb4c168d73689cae82be4fdea40334f701L7-L8

first, though.