Update documentation to reduce duplication in `Chatbots` and `Streams` sections

[isSerge]

Problem:
Currently every entry in Chatbots and Streams contains description of all config items, which results in duplication across all sections:
Chatbots:
https://rindexer.xyz/docs/start-building/chatbots/telegram
https://rindexer.xyz/docs/start-building/chatbots/discord
https://rindexer.xyz/docs/start-building/chatbots/slack
Streams:
https://rindexer.xyz/docs/start-building/streams/kafka
https://rindexer.xyz/docs/start-building/streams/rabbitmq
https://rindexer.xyz/docs/start-building/streams/sns
https://rindexer.xyz/docs/start-building/streams/redis
https://rindexer.xyz/docs/start-building/streams/webhooks

Proposed solution:

• Create dedicated pages for common config items (network, messages, etc.)
• Keep only transport- and stream-specific configuration details in above mentioned pages