Check that pnpm installed locally (not globally) works in the same way as globally installed

[denis-anisimov]

Initial part of #6966:

• we should not require (preferably) to have pnpm installed.
• if pnpm is installed globally we should use it.
• if there is no installed pnpm globally then we should install it locally (in node_modules folder): is it possible at all ?
  -check that locally installed pnpm works in the same way as globally installed: it uses global cache. Otherwise there is no sense to install it locally since different projects will have different scripts (with different locations).
• If it's possible to use local pnpm : create a method in the FrontendUtils class to get executable commend for pnpm ( see described algorithm above).

[denis-anisimov]

Locally installed npm seems is working in the same way as globally installed.
I don't see a difference.
If it's installed locally then the path to the JS is : node_modules/pnpm/bin/pnpm.js. (Inside a project dir).