Add configurable option to always link to environment front pages.

Problem/Motivation

For some projects, administrators may prefer cross-environment links to direct to a consistent specific path on the site instead of directly to the currently viewed page. To support the existing functionality, this should be a configurable option with a default value to match current functionality.

Steps to reproduce

Proposed resolution

• Add a new configuration setting in the module settings
• Manipulate generation of the environment links based on the new setting

Remaining tasks

User interface changes

Add a new "Path" field on the settings form for each environment.

API changes

Data model changes

New "path" configuration value in the "environment_indicator.switcher.*" configuration objects.