Similar to how cl/12253 already did this for `Signature`, we apply the
same logic to `StorePath`.
`StorePathRef<'a>'` is now a `StorePath<&'a str>`, and there's less
redundant code for the two different implementation.
`.as_ref()` returns a `StorePathRef<'_>`, `.to_owned()` gives a
`StorePath<String>` (for now).
I briefly thought about only publicly exporting `StorePath<String>`
as `StorePath`, but the diff is not too large and this will make it
easier to gradually introduce more flexibility in which store paths to
accept.
Also, remove some silliness in `StorePath::from_absolute_path_full`,
which now doesn't allocate anymore.
Change-Id: Ife8843857a1a0a3a99177ca997649fd45b8198e6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12258
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>
2beabe968c