Add a config system for bot customization.

[Owen3H]

Since this bot can be self-hosted, it should have some sort of config file system (TOML?) where users can edit options the bot will use instead of being hardcoded. This way, the user doesn't have update their fork or change code to receive/make these changes themselves.

Here is a small example:

BOT_NAME = "EMCS Rewritten"
PAGINATOR_TIMEOUT = 120 # The amount of time (sec) before a paginator will stop responding to buttons.
MESSAGE_DELETE = 10 # The amount of time (sec) before a message is deleted (usually in error cases).

[OAPI]
DOMAIN = "https://api.earthmc.net/v3/"
RATE_LIMIT = 180 # The amount of requests that can be sent in a minute.
QUERY_LIMIT = 100 # The amount of items each request query can contain.

[CACHE]
  [CACHE.MAPI]
    MARKERS = 60 # How often town/nation data should be cached in seconds.
    PLAYERS = 3 # How often online player data should be cached in seconds. Does not include underground players.

[Owen3H]

Achieved some progress towards this goal with 1dcf4c3.
This adds a new config package which enables safe interaction with .env and will support actual config files in future.