Improve output directory structure

Describe the bug

See the discussion on https://github.com/redhat-developer/yaml-language-server/pull/1104

The compiled code is split between two folders:

• ./out for the code compiled to CommonJS modules as well as a compiled copy of the test code
• ./lib for the code compiled to UMD modules and to ESM modules

Notably, the relative paths to ./l10n from the CommonJS server.js and the UMD and ESM server.js are different. This means that the localization information will not be loaded properly when running with the compiled UMD or ESM code.

Making changes to the output directory structure could break projects that consume yaml-language-server, but the current structure is confusing and causing problems.

Expected Behavior

1. There should be one "output" folder for the compiled code
2. The relative path from server.js to ./l10n for CJS, UMD, and ESM should be the same

Current Behavior

1. There are two output folders: out and lib
2. The relative path from server.js to ./l10n for CJS is ../../../l10n and for UMD and ESM it's ../../l10n

Steps to Reproduce

1. Compile the code npm run compile; npm run compile:esm; npm run compile:umd
2. Observe the directory structure of the output code

Environment

• Windows
• Mac
• Linux
• other (please specify)

Start with the output produced by npm run compile, npm run compile:esm, and npm run compile:umd, comparing the out and lib folders and the server.js paths to ./l10n. Read the discussion in pull request 1104 before changing the layout. Done means one output folder is used and CJS, UMD, and ESM resolve localization through the same relative path without breaking the documented compile commands.