apidom-reference: switch parser adapters to optional dependencies

[char0n]

The goal of this issue is to switch parser adapter dependencies to optional ones.

Why we're doing this?

apidom-reference package is in essence a framework. We can use this framework with two configurations:

When using empty configuration approach, options object is not configured with parsers, resolvers or strategies. This is suitable for creating web bundles and gives you total control of the contents of your bundles.

Saturated configuration is suitable for Node.js environments. options object is pre-configured with all the parsers, resolvers and strategies.

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If we switch all parser adapter dependencies to optional, it means that during installation, these dependencies may fail to install, but these failures will not fail overall apidom-reference installation. One can still use empty configuration approach and provide apidom-reference with his/hers own implementations of parser adapters.