feat: exclude and from creating new tokens in patterns

[benclive]

What this PR does / why we need it:
After reviewing the patterns generated in more environments, we've identified some punctuation which shouldn't split tokens.

• Excluding : and . as token split points - this makes timestamps + IP addresses tokenize as single tokens which makes it easier for Drain to categorise them.
• Some tokens won't be split as much which should improve performance a little.
• As usual, there may be some logs for which this causes problems.
• JSON logs are (luckily) unaffected because well-formed json will still split the quotes surrounding keys.

[cyriltovena]

LGTM