Develop a bootstrap command

As discussed in sylva-projects&56 and in sylva-units-operator#39 (closed), it would be relevant to start working on a sylvactl bootstrap command that would:

• Create kind cluster
• Bootstrap flux in that cluster
• Install the external secret operator and sylva-units-operator in it (using flux or plain manisfest - to be discsussed)

Some part of flux bootstrap are available as packages, but not the part that embeds and generates the manifests, so I feel that it would be simpler to embed all the manifests in sylvactl (flux, eso and swc)