getmesh command to select a distroless image for install

[batchamalick]

Currently we do not have a way to say/choose the distroless image to be used for any of the flavor at the time of install .
This request came from Microstrategy as they are seeing some CVE issue in the ubuntu based image.
Though we are releasing the image for distroless for every flavor .

[pmerrison]

@psbrar99 - turns out that this issue covers what we were talking about. Whilst we could add an option to get distroless rather than the ubuntu based version, I think we should just change the default to distroless and call it a day for now. I can't think of a use case where someone would choose an ubuntu based image over a distroless one anyway.

[psbrar99]

@batchamalick :
i tried installing with this command and see it is pointing to distroless images.
getmesh istioctl install --set profile=demo --set tag=1.13.2-tetrate-v0-distroless

[psbrar99]

@batchamalick @pmerrison : this is inline what is done in upstream and all the release artifacts( charts ) default to normal images. We can use the set hub and tag command to point it to different registry or images.

[psbrar99]

Instructions updated on the tetratelabs website .