ci: group dependabot updates and update code owners (FB-4445)

[fstr]

Summary

Updates the Dependabot configuration so that dependency updates are batched into one PR per ecosystem, instead of one PR per dependency.

• Ecosystems covered: github-actions, pip
• Each ecosystem has a single catch-all group (patterns: ["*"]).
• GitHub Actions are checked daily, and package dependencies weekly on Monday (UTC).
• A 7-day cooldown waits a week after a release before proposing an update.
• Sets @firebolt-db/team_infrastructure as the default code owner in .github/CODEOWNERS.

🤖 Generated with Claude Code

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Note

Low Risk
GitHub workflow and ownership metadata only; no application runtime or security logic changes.

Overview
Default review ownership moves from @firebolt-db/ecosystem-engineering to @firebolt-db/team_infrastructure for all paths in .github/CODEOWNERS.

Dependabot is reconfigured so each ecosystem opens one grouped PR (patterns: ["*"]) instead of per-dependency PRs. GitHub Actions run on a daily schedule (08:17 UTC) with up to 20 open PRs; pip covers / and /docs on weekly Mondays (08:30 UTC) with up to 10 open PRs. Both keep the chore(deps): prefix and 7-day cooldown after releases.

^{Reviewed by Cursor Bugbot for commit 75729fe. Bugbot is set up for automated code reviews on this repo. Configure here.}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud