Codespaces-related updates

[jessestorbeck]

These updates mostly relate to issues with developing Pushkin sites in GitHub Codespaces:

• Added logic to front end's config.js to automatically detect use in GitHub Codespaces and appropriately set API endpoints
• Added similar logic to front end's craco config to set WebSocket URL appropriately for Codespaces
• Added detection of Codespaces-specific environment variables to CLI's setEnv() function
• Added associated docs updates
• Non-Codespaces: Switched to self-hosting the font for the basic site template, which previously wasn't rendering and was causing warnings in the console

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 1b0810971292c87afbb7d716469afdde7497ef11

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

| Name | Type | | ----------------------------- | ----- | | @pushkin-templates/site-basic | Patch | | pushkin-cli | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR