If ~/.local/bin folder doesn't exist use fails to setup symbolic links

[adam-fowler]

There are too many places in the code base at the moment where errors are not caught and dealt with. The use function would throw an error and then that was it. We should catch this and create the folder.

[patrickfreed]

SWIFTLY_BIN_DIR, SWIFTLY_HOME_DIR, and SWIFTLY_HOME_DIR/toolchains are all created by each command before it runs if they don't exist, see here: https://github.com/patrickfreed/swiftly/blob/main/Sources/Swiftly/Swiftly.swift#L47. Can you share the error you were seeing / steps to reproduce it?

[adam-fowler]

I cannot remember anymore how I got this. It is kinda moot when running from the script as it sticks swiftly inside the ~/.local/bin folder. So the folder will always exist. But I do think we should be catching unexpected errors and trying to provided a readable error message from them.