Remove special-casing for editable requirements (#3869)

## Summary

There are a few behavior changes in here:

- We now enforce `--require-hashes` for editables, like pip. So if you
use `--require-hashes` with an editable requirement, we'll reject it. I
could change this if it seems off.
- We now treat source tree requirements, editable or not (e.g., both `-e
./black` and `./black`) as if `--refresh` is always enabled. This
doesn't mean that we _always_ rebuild them; but if you pass
`--reinstall`, then yes, we always rebuild them. I think this is an
improvement and is close to how editables work today.

Closes #3844.

Closes #2695.

crates/pypi-types/src/parsed_url.rs

@@ -33,6 +33,13 @@ pub struct VerbatimParsedUrl {
     pub verbatim: VerbatimUrl,
 }
 
+impl VerbatimParsedUrl {
+    /// Returns `true` if the URL is editable.
+    pub fn is_editable(&self) -> bool {
+        self.parsed_url.is_editable()
+    }
+}
+
 impl Pep508Url for VerbatimParsedUrl {
     type Err = ParsedUrlError;
 
@@ -150,6 +157,13 @@ pub enum ParsedUrl {
     Archive(ParsedArchiveUrl),
 }
 
+impl ParsedUrl {
+    /// Returns `true` if the URL is editable.
+    pub fn is_editable(&self) -> bool {
+        matches!(self, Self::Path(ParsedPathUrl { editable: true, .. }))
+    }
+}
+
 /// A local path url
 ///
 /// Examples: