feat: add pnpm binary - use pnpm for bootstrapping

[aminya]

This adds the pnpm binary to papm. This paves the way for using pnpm instead of npm in the papm itself.
It also builds papm using the bundled pnpm.

It also updates the build and CI configurations and code.

[aminya]

keytar fails to run the prebuild-install, because we run npm rebuild instead of pnpm rebuild inside postinstall script

> keytar@7.7.0 install /home/aminya/papm/node_modules/keytar
> prebuild-install || npm run build

internal/modules/cjs/loader.js:968
  throw err;
  ^

Error: Cannot find module '/home/aminya/[email protected]/node_modules/prebuild-install/bin.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:965:15)
    at Function.Module._load (internal/modules/cjs/loader.js:841:27)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
    at internal/main/run_main_module.js:17:47 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}

> keytar@7.7.0 build /home/aminya/papm/node_modules/.pnpm/keytar@7.7.0/node_modules/keytar
> node-gyp rebuild

Package libsecret-1 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libsecret-1.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libsecret-1' found
gyp: Call to 'pkg-config --cflags libsecret-1' returned exit status 1 while in binding.gyp. while trying to load binding.gyp
gyp ERR! configure error
gyp ERR! stack Error: `gyp` failed with exit code: 1
gyp ERR! stack     at ChildProcess.onCpExit (/home/aminya/papm/node_modules/.pnpm/[email protected]/node_modules/npm/node_modules/node-gyp/lib/configure.js:351:16)
gyp ERR! stack     at ChildProcess.emit (events.js:315:20)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)
gyp ERR! System Linux 5.10.43.3-microsoft-standard-WSL2
gyp ERR! command "/home/aminya/papm/bin/node" "/home/aminya/papm/node_modules/.pnpm/[email protected]/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /home/aminya/papm/node_modules/.pnpm/[email protected]/node_modules/keytar
gyp ERR! node -v v12.18.3
gyp ERR! node-gyp -v v5.1.0
gyp ERR! not ok
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build: `node-gyp rebuild`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/aminya/.npm/_logs/2021-07-23T01_29_24_373Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] install: `prebuild-install || npm run build`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the keytar@7.7.0 install script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/aminya/.npm/_logs/2021-07-23T01_29_24_394Z-debug.log

[aminya]

I added the pnpm binary, which fixes the npm rebuild issue by using pnpm rebuild instead.

[aminya]

There is a loop here because of running postinstall script

[aminya]

This now works perfectly under macos and linux. I need to fix Windows now.