Add Algolia DocSearch to navbar

[aridyckovsky]

Is your feature request related to a problem? Please describe.
As the website expands in content, a searchable interface will be very helpful.

Describe the solution you'd like
We're will try to use https://docsearch.algolia.com/ because it integrates seamlessly with Docusaurus sites. See https://docusaurus.io/docs/api/themes/@docusaurus/theme-search-algolia for more details.

[aridyckovsky]

Note: I've already applied for an index and API key via https://docsearch.algolia.com/apply/, as required for https://docusaurus.io/docs/2.0.0-alpha.72/search#connecting-algolia

[aridyckovsky]

Received a reply stating that our site does not fit within the criteria to be indexed with DocSearch. The reason stated was that the site was evaluated as not documentation. It seems to me that the issue may be the early-stage nature of the documentation. I've followed up to inquire further, and it may just be a "wait and try again later" situation.

[aridyckovsky]

Update on the previous comment: DocSearch is a suitable option and we can use it, but we will need to have a more developed site before indexing can take place