feat: sprig support (bcrypt, htpasswd)

[lukasmrtvy]

Would be great to support https://github.com/Masterminds/sprig library, bcrypt and htpasswd fnctions are definitely useful when comes to deploying webservers. Sprig is used in Helm.

Thanks

[CertainLach]

Both bcrypt and htpasswd are non-deterministic (Because of random salt), but jsonnet is designed to be side-effect free

[sbarzowski]

We could have the salt explicitly provided by the user (as a function argument). That said, it is a fairly difficult thing to add without breaking compatibility with other implementations. I'm aware of experimental work which would provide a general solution to that, but don't expect it anytime soon.