Refactor bootstrap configuration to use dynamic runtime layers

[MeenuyD]

In contour/internal/envoy/v3/bootstrap.go, removed the static bootstrap runtime layer. Instead, this modifies the bootstrap configuration to use dynamic runtime layers, allowing for more flexibility and consolidation of the codebase.
#5845

[github-actions]

Hi @MeenuyD! Welcome to our community and thank you for opening your first Pull Request. Someone will review it soon. Thank you for committing to making Contour better. You can also join us on our mailing list and in our channel in the Kubernetes Slack Workspace

[sunjayBhatia]

Hey @MeenuyD thanks for the PR!

A few things that will need to be fixed:

• please sign off your commits (git commit --signoff) to make sure the DCO check passes
• We also wanted to refactor this file https://github.com/projectcontour/contour/blob/main/internal/envoy/v3/runtime.go to move the regex program size settings into the runtimeKV settings at this higher level
• The previous bullet and your existing changes will need appropriate unit test changes

[github-actions]

The Contour project currently lacks enough contributors to adequately respond to all PRs.

This bot triages PRs according to the following rules:

• After 14d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, the PR is closed

You can:

• Mark this PR as fresh by commenting or pushing a commit
• Close this PR
• Offer to help out with triage

Please send feedback to the #contour channel in the Kubernetes Slack

[github-actions]

The Contour project currently lacks enough contributors to adequately respond to all PRs.

This bot triages PRs according to the following rules:

• After 14d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, the PR is closed

You can:

• Mark this PR as fresh by commenting or pushing a commit
• Close this PR
• Offer to help out with triage

Please send feedback to the #contour channel in the Kubernetes Slack

[github-actions]

The Contour project currently lacks enough contributors to adequately respond to all PRs.

This bot triages PRs according to the following rules:

• After 14d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, the PR is closed

You can:

• Ensure your PR is passing all CI checks. PRs that are fully green are more likely to be reviewed. If you are having trouble with CI checks, reach out to the #contour channel in the Kubernetes Slack workspace.
• Mark this PR as fresh by commenting or pushing a commit
• Close this PR
• Offer to help out with triage

Please send feedback to the #contour channel in the Kubernetes Slack