Add more details on how to start / reload a bot during testing

[brad90four]

Description

Add more information on how to run or reload a bot during testing to the contributing guides.

Reason

For people who are new to using Docker / discord.py / contributing to python-discord/bot or python-discord/sir-lancebot, this will be a helpful resource on how to test small changes during the development stage (or review).

Proposed Implementation

Based on a short discussion in #dev-contrib [message link], this is a short and possibly incomplete overview of how to start / reload a bot:

1. Stop and Start Docker from the desktop application or from the command line docker start -d snekbox redis postgres web , docker-compose up , etc (not recommended)
2. With poetry: poetry run task start from the root, if outside the venv or task start if inside the venv
3. py -m <bot/sir-lancebot> from the root, inside the venv
4. Set up a run task (automatically run py -m <bot/sir-lancebot>)
5. If changing a cog, reload cog from the discord channel with !c r <cog> or .c r <cog>

This summary can be a new section in the pages here:
sir-lancebot contributing guide

pydis_site/apps/content/resources/guides/pydis-guides/contributing/sir-lancebot.md

or here:

bot contributing guide

pydis_site/apps/content/resources/guides/pydis-guides/contributing/bot.md

[brad90four]

Closed with bot#591