Update Infracost configuration and variable descriptions

[brettcurtis]

This pull request updates the Infracost configuration and variable descriptions.

[infracost]

Infracost report

💰 Monthly cost will increase by $2 📈

Project	Cost change	New monthly cost
default_cloud_sql	+$2 (+11%)	$21

Cost details

──────────────────────────────────
Project: default_cloud_sql
Module path: test/fixtures/default_cloud_sql

~ module.test.google_sql_database_instance.this
  +$2 ($19 → $21)

    ~ Backups
      +$2

Monthly cost change for default_cloud_sql (Module path: test/fixtures/default_cloud_sql)
Amount:  +$2 ($19 → $21)
Percent: +11%

──────────────────────────────────
Key: ~ changed, + added, - removed

3 cloud resources were detected:
∙ 1 was estimated, it includes usage-based costs, see https://infracost.io/usage-file
∙ 2 were free, rerun with --show-skipped to see details

Infracost estimate: Monthly cost will increase by $2 ↑
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━┓
┃ Project                                            ┃ Cost change ┃ New monthly cost ┃
┣━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━┫
┃ default_cloud_sql                                  ┃  +$2 (+11%) ┃ $21              ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━━━━┛

Governance checks

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48 FinOps policies, 1 Tagging policy, and 1 Guardrail passed.

_{View in Infracost Cloud. This comment will be updated when code changes.}