Developers with `direnv` installed will have ./tools added to their
PATH automatically. Also adds it to the PATH in the dev container.
This reduces `tools/dev_container tools/presubmit` to
`dev_container presubmit`.
Note: Does not rebuild the container, the change can be picked
up at a later time.
BUG=None
TEST=cd crosvm
Change-Id: Ia57bd7bb1cf86df2b32d624d97a74518e8b5f423
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/4305345
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Dennis Kempin <denniskempin@google.com>
