DX: ease the requirements installation

[raskyld]

Is your feature request related to a problem? Please describe.
The Taskfile and the opinionated development environment shipped with go-tektasker requires other tool:

• ko builder
• kubectl and a valid context pointing to a cluster with tekton installed
• task to run the taskfile

This may hurt DX and create an useless barrier to use Tektasker.

Describe the solution you'd like

An installer that SHOULD install task, ko and propose to install Tekton Pipelines to the current Kubernetes
context if the CRDs are not found. It should be easy to maintain and to read so the user isn't
scared to launch it. (more likely a bash script right?)

It should be interactive (asks the user for permission) and use go install for task and ko so we don't have to deal with
arch and OS specificities.