Add perplexica

[peterclemenko]

Checked

• I searched existing ideas and did not find a similar one
• I added a very descriptive title
• I've clearly described the feature request and motivation for it

Feature request

Adding https://github.com/ItzCrazyKns/Perplexica to langchain would allow for open source search to be easily called from langchain

Motivation

sometimes local search is better than a SAAS

Proposal (If applicable)

No response