Add support for postgres stored procedures

[AndrewJackson2020]

This PR adds support for stored procedures in the provider. Since stored procedures are very similar to functions i based much of this implementation off of the preexisting code for functions.

Also I changed the shebang in some of the bash files so that it works on operating systems where bash is not located at /bin/bash (NixOS for example). I think this should not cause issues on operating systems where bash is located there but if it does cause any issues I am happy to revert that.

Please let me know if you see any issues and I will be happy to fix.

[rubentsirunyan]

I’ve tested this by creating, updating, and deleting procedures, and it worked perfectly! Thanks @AndrewJackson2020 !

@cyrilgdn , it would be fantastic if the provider could support stored procedures like it supports functions.

[AndrewJackson2020]

Yeah I mean it's fully unit tested so I would expect it to work, might be some edge cases that I missed though. Would be more than happy to document as well if there was any interest in merging. Unfortunately there has not been any commits to this project in around 6 months so I'm not super hopeful.