Improve rendering performance for high number of fields

## Expected Behavior

The search should load and be usable for a high number of fields (in the order of n*10^3).

## Current Behavior

In some setups, the search page takes quite long to load if a lof of fields exist.

## Possible Solution

## Steps to Reproduce (for bugs)

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## Context

## Your Environment

* Graylog Version:
* Java Version:
* Elasticsearch Version:
* MongoDB Version:
* Operating System:
* Browser version:

HS-698487408