Add Unix-like command-line argumets

[gurland]

1. Add some basic arguments like -help
2. Provide examples and help in README.md

[gurland]

From ixearth's reply to #5

I would recommend to add multiple command-line arguments such like

-type group supergroup -id

The value of -type can be private, group, supergroup or channel, the id can be chat id of any of them (the one need to add quote characters when the id was negative number). Users should also be able to get chat IDs by using the script.

btw is "Saved Message" also being considered as personal chat? If it is then maybe it should be noted in the help message to avoid data loss. the one may don't think "Saved Message" as any of that four chat type. (you may add the dialogue to ask user to type yes to confirm, it won't be a problem if the one could run it as yes | cleaner.py when he needs to run it in non-interactive mode)

The reason I need to delete all of my chat message is I want to delete them before I delete my account, this use case is very rare, so I think -type is enough for such needs and -all is not necessary.

I need to delete messages from certain groups and private chats every period of time, so -id would be much useful for me to run the script with crontab.

[gurland]

A BraveSail suggestion in #49

It would be great to use a command line with args to exclude or include some groups by ID, So people can write a crontab schedule to delete messages during a specified time.