loader: update for 20.0.0/21.0.0

pgl/pm: add GetProcessId command

kern: fix debug build for [[nodiscard]] changes

kern: fix whoops introduced by nodiscard refactor

erpt: implement new 21.0.0 commands

erpt: fix ids, failed to copy the new categories

fatal: add new HashedTraceContext command

erpt: add new IDs for 21.0.0

kern: exception flags are now atomic. ...

This is a really weird one, because they didn't actually update the
code which updates these flags in asm, these still use ldrb/orr/strb.
But every access to these via c++ is now an atomic ldxrb/stxrb loop.
Maybe they just forgot to update the asm?

kern: pass u32 directly to CopyMemoryToUserSize32Bit

ams: mark ams::Result [[nodiscard]] (partially complete). ...

NOTE: This work is not yet fully complete; kernel is done, but
it was taking an exceedingly long time to get through libstratosphere.
Thus, I've temporarily added -Wno-error=unused-result for libstratosphere/stratosphere.

All warnings should be fixed to do the same thing Nintendo does as relevant, but this
is taking a phenomenally long time and is not actually the most important work to do,
so it can be put off for some time to prioritize other tasks for 21.0.0 support.

kern: Nintendo now also devirtualizes KAutoObject::DynamicCast

kern: write cpu tick differential to tls +0x108 on thread switch

fusee/exo/ams: update with new keydata/version enums

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "583ae0fbf"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "583ae0fbf"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

fssystem: fix support for parsing newer-format BKTR NCAs ...

Apparently, at some point they started allowing maxlayers=3, which caused this code to not work.

Looking at latest FS, they always reference DataStorage instead of level+2 for the final level.

This fixes parsing update romfs for newer games, e.g. Super Mario Galaxy 2.

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "efd3d931a"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "efd3d931a"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

ams: bump version, add enum support for 20.5.0

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "bbd085442"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "bbd085442"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

ams: bump version, add enum support for 20.4.0

build: portability fixes ...

- Invoke Python scripts with `python3` if `python` is not available.

  Despite SciresM preferring Python 2, the scripts used in the build all
  worked in Python 3 already, so this is just a Makefile change.

- Export `MAKE` to work around a GNU bug.

  See the comment for details.

- `rmdir --ignore-fail-on-non-empty` -> `rmdir 2>/dev/null`

  macOS `rmdir` doesn't support `--ignore-fail-on-non-empty`.

  This is a slight downgrade in functionality, because now we ignore all
  errors from `rmdir` rather than just 'Directory not empty'.  I could
  have avoided this with a more complicated fix, but the benefit strikes
  me as not worth the complexity.  Let me know if you disagree.

- Append `$(DEVKITPRO)/tools/bin/` to `$PATH` when invoking
  `build_romfs`.

  This avoids the need to add devkitPro directories to `$PATH` when
  building Atmosphere.

  If you already have `build_romfs` in your PATH, then that will still
  take precedence.  (This seemed like the nicer option, though I don't
  have strong opinions.)

haze: fix duplicate-macro warnings ...

haze was including both `<switch.h>` and `vapours/types.hpp` which both
define `R_SUCCEEDED` and `R_FAILED`, producing compiler warnings.

The intent is that `vapours/types.hpp` only gets included when targeting
not-Switch and/or not-EL0.  But the check didn't account for
Troposphère.  Fix that.

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "bc7a0fc11"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "bc7a0fc11"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

ams: bump version, support 20.3.0

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "af10bca1b"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "af10bca1b"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

ams: bump version, add 1.9.2 changelog

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "4e3615355"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "4e3615355"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

ams: add enum version support for 20.1.x/20.2.0

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "0f72b2ceb"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "0f72b2ceb"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

kern: move spendsgir static assert