Implement docs search functionality

[mihaiblaga89]

• [x] create algolia free account
• [x] implement algolia api into docs

Deployed for testing:

• https://renative-docs-testing-git-feat-addsearch-flexn-io.vercel.app/

[GabrieleKaceviciute]

@mihaiblaga89 @Marius456 how should this be tested?

[pauliusguzas]

I don't think search works as expected:

1. All results seem to be bundled into one pressable component

2. When user enters something, found text is highlighed and there is also space added which looks weird (maybe expected?)

3. Space seems to work as "OR" operand, by default all search engines treat it as "AND", atleast that is what I noticed

Also after clicking on results https://renative.org/ url opens, probably expected as this is testing environment