Configure git plugin

Basic configuration of the Git Client plugin

sample configuration

tool:

git:

installations:

- name: git

home: /bin/git

- name: another_git

home: /usr/local/bin/git

implementation note

Here we rely on hudson.tools.ToolDescriptor.setInstallations, so same applies to all ToolInstallations. Unfortunately Java reflection makes it hack-ish to detect the parameter type of this method from derived concrete class, so maybe there's some corner case we will need to polish this logic.

Also, YAML lists are converted into ArrayLists but setInstallations(T ... installation) varags method require an array - blame Java to not just accept any Iterable - so we need to detect this scenario and do the type conversion.