Documentation mistakes in TB-website

[georgimld]

• [x] I have searched the issues of this repository and believe that this is not a duplicate.

Description 😯

The documentation section "Connect to an existing Blockchain network using docker" has some mistakes. The descriptions for EXTERNAL_IP and P2P_HOST are not correct, and should be fixed as follows:

• EXTERNAL_IP: this environement variable should be set on the Alpha blockchain node and should contain the public ip address and port of the Alpha blockchain.
• P2P_HOST: this environment variable should be set on the Beta blockchain node and should contain the public IP-address of the Alpha node (where the node should connect to)

Also, the descriptions should be more clear to avoid misinterpretation

Your Environment 🌎

Tech	Version
TruBudget	v2.0.0