Auto merge of #10265 - epage:clap-port, r=joshtriplett

Auto merge of #10265 - epage:clap-port, r=joshtriplett

Port cargo to clap3

### What does this PR try to resolve?

This moves cargo to the latest major version of clap.

This supersedes #10259  and #10262

### How should we test and review this PR?

For testing, I mostly relied on existing tests.  I did manually validate that `cargo run <non-escaped command args>` behaved the same between both
```console
$ cargo run release --help
    Finished dev [unoptimized + debuginfo] target(s) in 0.22s
     Running `target/debug/cargo-release release --help`
cargo-release 0.18.8
...

$ cargo run --manifest-path ../cargo/Cargo.toml -- run release --help
    Finished dev [unoptimized + debuginfo] target(s) in 0.05s
     Running `/home/epage/src/personal/cargo/target/debug/cargo run release --help`
    Finished dev [unoptimized + debuginfo] target(s) in 1.31s
     Running `target/debug/cargo-release release --help`
cargo-release 0.18.8
...
```

For reviewing, I split out each deprecation resolution into a separate commit so its easy to focus on more mechanical changes (most of the deprecation fixes) from interesting ones (the port, the `Arg::multiple` deprecation)

### Additional information

- One parser change found by `cargo_config::includes` is that clap 2
  would ignore any values after a `=` for flags.
  `cargo config --show-origin` is a flag but the test passed `--show-origin=yes` which
  happens to give the desired result for that test but is the same as
  `--show-origin=no` or `--show-origin=alien-invasion`.
- `ArgMatches` now panics when accessing an undefined argument but clap
  takes advantage of that for sharing code across commands that have
  different subsets of arguments defined.  I've extended clap so we can
  "look before you leap" and put the checks at the argument calls to
  start off with so its very clear what is tenuously shared.  This
  allows us to go in either direction in the future, either addressing
  how we are sharing between commands or by moving this down into the
  extension methods and pretending this clap feature doesn't exist
- On that topic, a test found clap-rs/clap#3263.  For now, there is a
  hack in clap.  Depending on how we fix that in clap for clap 4.0, we
  might need to re-address things in cargo.
- `value_of_os` now requires setting `allow_invalid_utf8`, otherwise it
  asserts.  To help catch this, I updated the argument definitions
  associated with lookups reported by:
  - `rg 'values?_os' src/`
  - `rg 'values?_of_os' src/`
- clap now reports `2` for usage errors, so we had to bypass clap's
  `exit` call to keep the same exit code.
- `cargo vendor --sync` did not use `multi_opt` and so it has both
  multiple occurrences **and** multiple values.  If we want to deprecate
  this, we'll need `unstable-grouped` to be stablized (or pin our clap
  version) and ensure each group has only 1 value.