Add warning or delete <func-root>/.s2i for older functions

[gauron99]

created as a follow-up based on #3436 (comment)

Add a warning when deploying via s2i builder after the PR mentioned above is merged (since its changing the s2i scaffolding paths).
Alternatively it might also straight up delete the .s2i/ directory. Or maybe prompting for the deletion with a note like "hey this is old s2i scaffolding, you are using ... its not needed anymore, can I proceed deleting this?" -- that way the user does not have much to deal with... something to consider.

[Kunal1522]

hey @gauron99 can i take this up ?

[lkingland]

This should be fine to pick up @Kunal1522. Just comment if you do.