fix(l1): modify Grafana dashboards so they can be filtered by instance

[klaus993]

Motivation

The Ethrex L1 Perf grafana dashboard currently doesn't let us filter by instance, it only works as a standalone dashboard for 1 ethrex instance.

Description

The instance filter now has a regex to avoid having to choose from each prometheus target: server:port and instead just filter by server and let it choose the port according to the different metric each pane needs to check

Closes #4976

[mpaulucci]

I see this is actively being worked on. Converting to draft, please convert to review once its ready

[rodrigo-o]

Apart for adding support for multiple servers (instances) to be able to compare different runs, the dashboard had major improvements:

• Better separation of panels thanks to rows
• Moved block building related panel to a WIP section (they are not as tested/checked as the other metrics/panels)
• Reduce scrape time to 5s to be able to account for more blocks (some were missing on 12s scrape time)
• Replaced the Block time & Gas Used % panel with two different ones
  • GGas/s by block
  • Block time by block
• made the block execution breakdown repeated by instances

This still have some points to address in follow up PRs here are 2 issues that we need to tackle:

• Add documentation about the limitations of the GGas/s by block panels in grafana #5048
• Remove repeated block brackdown on local grafana execution #5049

Main	This PR

[Copilot]

Pull Request Overview

This PR enhances the Grafana dashboards to support filtering metrics by instance using a regex pattern. The main improvement allows users to filter by server name (e.g., ethrex-mainnet-3-0-0) instead of requiring the full server:port format, with the regex automatically matching the appropriate port for each metric.

Key changes:

• Modified instance filter variable to use regex pattern /^(?<text>[^:]+)(?::\\d+)?$/ for extracting server names
• Updated metric queries across all dashboards to use instance=~\"$instance(:\\\\d+)?$\" pattern
• Converted several stat panels to table format for better multi-instance visualization

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
ethrex_l1_perf.json	Updated instance filtering with regex, converted stat panels to tables, reorganized dashboard layout with new sections
ethrex_comparison.json	New dashboard added for comparing ethrex performance against other Ethereum clients across different networks
ethereum_metrics_exporter.json	Updated instance filtering with regex, converted stat panels to tables for multi-instance support

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[rodrigo-o]

This PR also added a new dashboard intended for internal use, comparing some instances of other clients in the same panel.