Adding inkeep widget

[nick-inkeep]

What change does this PR introduce?

Three major things:

1. Added the Inkeep search and chat widget

Inkeep's search and chat experience to Novu's docs. It's trained on Novu documentation, GitHub issues, and Discord threads.

2. Moved to Docusaurus V3

Inkeep's widget has a dependency on React 18, which is the primary purpose of the Docusorous V3 release (alpha).

Few key things that I did in order to support this:

1. upgraded dependencies to use V3, including the new new mdx-js version, and react 18.
2. renamed all .md files to "mdx"
3. Addressed certain invalid mdx formatting issues. For example, all JSX must be wrapped with { } now. Links, like https://mydomain.com that aren't HTML tags must either be ticked marked `` or use .

3. Addressed previously existing yarn 'check' issues

Prior to upgrading to V3, I did yarn check to see the current state of dependencies. Here were the original yarn check issues, prior to any changes:

I addressed these issues by adding missing dependencies or devDependencies or updating certain versions.

Result

I have tested what I could and I don't see any breaking changes. It seems stable.

Why was this change needed?

Add Inkeep's search and chat service to Novu's documentation.

Remaining yarn warnings

Notes:

1. Algolia warnings can be ignored because Algolia is no longer being used
2. react-json-view warnings have been addressed and will be in the next release. See here.
3. docusaurus-plugin-sass - not sure if this affects anything, but I filed a GitHub issue asking for clarification here.

Screenshots

[github-actions]

Pull reviewers stats

Stats of the last 30 days for novu:

	User	Total reviews	Time to review	Total comments
	p-fernandez	48	1h 45m	147
	scopsy	15	24m	3
	LetItRock	14	17h 47m	58
	djabarovgeorge	14	1d 10h 24m	51
	ainouzgali	10	43m	50
	unicodeveloper	8	7d 8h 31m	96
	davidsoderberg	5	15h 55m	3
	BiswaViraj	2	10h 44m	1
	jainpawan21	2	7h 59m	2
	peoray	1	27m	1
	michaldziuba03	1	10h 53m	1
	Cliftonz	1	5d 54m	0

[p-fernandez]

Thanks for your contribution.
Could you please elaborate more why this PR is needed?

[unicodeveloper]

@p-fernandez We have a contract with inKeep. So now we are trying to add it to the docs to test how it works and also monitor how valuable it is for us.