added manual kubernetes tls certs to the cert-expire finder

[seppelucas]

function list_k8s_cert_expiry_days has been extended to check manual set tls certs and add their expire to the output list.

this is done by checking for an annotation cert-manager provides. when there is no certificate object surrounding the secret we manual need to check the end date with openssl x509

[seppelucas]

it is also a possibility too get all tls secrets and check them this way. without the special function for the cert-manager secrets. but i think that for the cert-manager secrets checking the status is faster then using openssl.

[wdoekes]

:+1:

Just one:

# wc -L cert-expiry-finder
88 cert-expiry-finder

But I'll fix that up with a little tweak now.