Add Best practices article (#186)

* Add aside about using only one corestore instance per application

A single corestore instance covers all needs and avoids pitfalls (such
as file locks and named hypercores not being the same key) that come
from multiple corestore instances.

* Add note for best practice to create one hyperswarm instance per app

* Create a best practices guide for Pear Application development

* Add "Best Practices" article to SUMMARY.md & README.md

* Include points added to the guides on using single swarm & store

* Fix capitalization in Best Practices article

howto/connect-to-many-peers-by-topic-with-hyperswarm.md

@@ -66,3 +66,5 @@ pear run --dev .
 This will display the topic. Copy/paste that topic into as many additional terminals as desired with `pear run --dev . <SUPPLY TOPIC HERE>` (assuming that the current working directory of each terminal is the `peer-app` folder). Each peer will log information about the other connected peers.
 
 Start typing into any terminal, and it will be broadcast to all connected peers.
+
+> It is best practice to only have one Hyperswarm instance per application. This will speed up connections by reducing number of entries per topic and connections.

howto/work-with-many-hypercores-using-corestore.md

@@ -6,6 +6,11 @@ An append-only log is powerful on its own, but it's most useful as a building bl
 
 In [How to replicate and persist with Hypercore](./replicate-and-persist-with-hypercore.md), only single Hypercore instance was replicated. But in this how-to, we will replicate a single Corestore instance, which will internally manage the replication of a collection of Hypercores. We will achieve this with two Pear Terminal Applications: `multicore-writer-app` and `multicore-reader-app`.
 
+> Only one Corestore per application is needed. This is the recommended best practices to make managing Hypercores efficient and to avoid pitfalls from having multiple Corestores. A single Corestore will:
+> - Manage multiple sessions for the same Hypercore.
+> - Requires only one replication stream per peer connection.
+> - Simplifies referring to Hypercores by a name.
+
 Create the `multicore-writer-app` project with these commands:
 
 ```