Add named Linea networks to Besu and Maru

## Description
Add named Linea networks to Besu and Maru

## Motivation
Less configuration is required, and easier release management.

## Tasks
- [ ] Add named Linea networks to Besu and Maru
- [ ] Apply changes to the documentation
- [ ] Apply changes to `docs/getting-started/linea-*`
- [ ] Ensure an HF release can be done relatively quickly <4h