UX ONLY: Docker buildx support

[uxarya-d]

Summary

Enable users to build image for desired platforms

Motivation

Presently, Devtron runs CI pipelines with docker build command which we think is hardcoded as part of CI step. We would want to use docker buildx command which supports a lot of features on top of the good old docker build. buildx would help us in building multi-platform images which can run on all types of processors.

Proposal

1. [Checkbox] Set the target platforms for the build

2. When user checks the above box, show a multi-select dropdown with below options:

linux/arm64
linux/amd64
linux/arm/v7
darwin

NOTE: User should also be able to provide custom input (free text).