#156977411 Implement Parser

[appcypher]

What does this PR do?

This PR implements a packrat parser and it is expected to be faster than the old parser.

Description of Task to be completed?

• Create a packrat parser.
• Reduce boilerplate stuff by having a basic parser combinator built in.
• Write tests for parser.
• Add a custom deep-equal implementation for tests.
• Improve testing library; add for support travis and coverage report.

How should this be manually tested?

• Install necessary packages with npm i.
• Run parser test, node src/compiler/syntax/parser-tests.js.
• The parser.js file is self-contained, it can be imported and used in other files.

What are the relevant pivotal tracker stories?

156977411

Project Story

https://github.com/astrolang/astro/projects/1#card-12436138