feat: devcontainer part 3 (#3318)

* stash initial fixes, attempt to open branch inside container

Signed-off-by: Dave Lee <dave@gray101.com>

* add yq, from inside DC

Signed-off-by: Dave Lee <dave@gray101.com>

* stash progress, rebuild container

Signed-off-by: Dave Lee <dave@gray101.com>

* snap

Signed-off-by: Dave Lee <dave@gray101.com>

* split builder into builder-sd, will speed up devcontainer build times and potentially help caching in other situations.

Signed-off-by: Dave Lee <dave@gray101.com>

* fix yq

Signed-off-by: Dave Lee <dave@gray101.com>

* fix paths

Signed-off-by: Dave Lee <dave@gray101.com>

* fix paths - new folder to bypass the .dockerignore which _should_ exclude the other files

Signed-off-by: Dave Lee <dave@gray101.com>

* fix

Signed-off-by: Dave Lee <dave@gray101.com>

* fix ]

Signed-off-by: Dave Lee <dave@gray101.com>

---------

Signed-off-by: Dave Lee <dave@gray101.com>

.devcontainer/customization/README.md

@@ -0,0 +1,20 @@
+Place any additional resources your environment requires in this directory
+
+Script hooks are currently called for:
+`postcreate.sh` and `poststart.sh`
+
+If files with those names exist here, they will be called at the end of the normal script.
+
+This is a good place to set things like `git config --global user.name` are set - and to handle any other files that are mounted via this directory.
+
+An example of a useful script might be:
+
+```
+#!/bin/bash
+gcn=$(git config --global user.name)
+if [ -z "$gcn" ]; then
+    git config --global user.name YOUR.NAME
+    git config --global user.email YOUR.EMAIL
+    git remote add PREFIX FORK_URL
+fi
+```