feat: support arbitrary uid for openshift environments

[jkleinlercher]

Closes #440

📑 Description

with this PR k8sgpt should also be able to run with an arbitrary uid. that is necessary especially in openshift environments because there by default the restricted-v2 SCC sets a uid in the securityContext. currently it depends on uid 65532 because k8sgpt wants to create a .config folder in the users home dir (

k8sgpt/cmd/root.go

Line 88 in 6479cba

configDir := filepath.Join(xdg.ConfigHome, "k8sgpt")

).

since only uid 65532 has a home dir defined in the distroless image an arbitrary uid would want to create the .config dir in the root folder, which is not allowed. so with this PR the XDG_ variables are pointing to a different folder which gets mounted as an emptyDir volume.

✅ Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

ℹ Additional Information

[AlexsJones]

The code looks good but I have no ability to test this, @jkleinlercher does this work on OS environments?