Support cases where EDM is already available

[itziakos]

When using custom (i.e.) github runners it is often the case that EDM is already available. It would be nice that the setup-edm-action could handle this usecase.

For example a new property min-version is supported and:

(a) If edm exists and min-version is not set then nothing happens
(b) if edm exists but edm-version < min-version then a warning/error is raised
(c) if edm is not available then edm is installed