feat(cwd-pane): Keeping the cwd when opening new panes (#691)

* feat(cwd-pane): Add a new trait to get the cwd of a given pid

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Allow for setting the cwd when spawning a new terminal

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Add an active_pane field to the Pty struct

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Update Pty with Tab's active pane id

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Refactor spawn_terminal to use cwd by default

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Fix tests and lints

Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

* feat(cwd-pane): Fix formatting

* feat(cwd-pane): Refactor child pid fetching to handle errors better

Instead of panicking when transfering the process id of the forked child
command we just return an empty process id.

* feat(cwd-pane): Add non Linux/MacOS targets for the get_cwd method.

This will allow Zellij to compile on non Linux/MacOS targets without
having an inherited cwd.

* feat(cwd-pane): Refactor spawn_terminal method to use ChildId struct.

The spawn_terminal methods been refactored to use the ChildId struct in
order to clarify what the Pid's returned by it are. The documentation
for the ChildId struct was improved as well.

* feat(cwd-pane): Fix tests/lints

Co-authored-by: Jesse Tuchsen <not@disclosing>
Co-authored-by: Quentin Rasmont <qrasmont@gmail.com>

zellij-server/Cargo.toml

@@ -12,6 +12,7 @@ license = "MIT"
 ansi_term = "0.12.1"
 async-trait = "0.1.50"
 base64 = "0.13.0"
+byteorder = "1.4.3"
 daemonize = "0.4.1"
 serde_json = "1.0"
 unicode-width = "0.1.8"
@@ -23,6 +24,9 @@ log = "0.4.14"
 typetag = "0.1.7"
 chrono = "0.4.19"
 
+[target.'cfg(target_os = "macos")'.dependencies]
+darwin-libproc = "0.2.0"
+
 [dev-dependencies]
 insta = "1.6.0"