Ensure all metadata fields are picked up

[ties]

Update the list of metadatafields that are turned into a metric. Current:

// curl https://console.rpki-client.org/rpki.json --compressed | jq '.metadata'
{
  "buildmachine": "psm-vrp-gen1.rpki-client.org",
  "buildtime": "2024-03-29T09:34:06Z",
  "elapsedtime": 603,
  "usertime": 365,
  "systemtime": 263,
  "roas": 198260,
  "failedroas": 13,
  "invalidroas": 0,
  "spls": 1,
  "failedspls": 0,
  "invalidspls": 0,
  "aspas": 98,
  "failedaspas": 30,
  "invalidaspas": 0,
  "bgpsec_pubkeys": 3,
  "certificates": 42270,
  "invalidcertificates": 1,
  "taks": 0,
  "tals": 5,
  "invalidtals": 0,
  "talfiles": [
    "/etc/rpki/afrinic.tal",
    "/etc/rpki/apnic.tal",
    "/etc/rpki/lacnic.tal",
    "/etc/rpki/ripe.tal",
    "/etc/rpki/arin.tal"
  ],
  "manifests": 42269,
  "failedmanifests": 113,
  "crls": 42156,
  "gbrs": 2,
  "repositories": 156,
  "vrps": 538620,
  "uniquevrps": 529250,
  "vsps": 1,
  "uniquevsps": 1,
  "vaps": 68,
  "uniquevaps": 68,
  "cachedir_new_files": 461,
  "cachedir_del_files": 12,
  "cachedir_del_dirs": 278,
  "cachedir_superfluous_files": 54192,
  "cachedir_del_superfluous_files": 236
}