Replace humacs/humacs with sharingio/environment

[BobyMCbobs]

Environment is a much cleaner project for providing what Humacs does. It also providers a rewritten way of exposing local services.

TODO

• update targets for tmate command/url
• update targets for pair-ssh-instance

Later

The namespace where Environment lives should be moved to the default namespace.

[BobyMCbobs]

Migrated over with https://github.com/sharingio/pair/commit/bae2ec8cbb5b18d206e5bf0e87c75cf76c5d026f