Removed the dependency on the base image, and instead install the needed packages in the Dockerfiles for debug and CNI.
Also removed some obsolete info from BUILD.md
Signed-off-by: Ali Ariff <ali.ariff12@gmail.com>
The `proxy` and `web` Docker images were 161MB and 186MB, respectively.
Most of the space was tools installed into the `linkerd.io/base` image.
Decrease `proxy` and `web` Docker images to 73MB and 90MB, respectively.
Switch these images to be based off of `debian:stretch-20190812-slim`.
Also set `-ldflags "-s -w"` for `proxy-identity` and `web`. Modify
`linkerd.io/base` to also be based off of
`debian:stretch-20190812-slim`, update tag to `2019-09-04.01`.
Fixes#3383
Signed-off-by: Andrew Seigner <siggy@buoyant.io>