Update renovate config to use data-sources base preset

[kevinwcyu]

Updates the renovate configuration to use the Grafana data-sources base preset

• Extends grafana-renovate-config//presets/data-sources/base preset
• Reduces minimum release age from 7 to 3 days to match default global renovate settings (we've had problems with setting it to 7 because the self-hosted renovate doesn't respect the repo level minimum release age setting and we haven't been able to figure out why yet. The base preset sets it to 7 days so this just overrides that setting)
• Adds prConcurrentLimit: 10 to override the limit of 3 set in the preset