After #750, we should validate that MongoDB collection names are valid.

MongoDB rules are documented here: https://www.mongodb.com/docs/manual/reference/limits/#mongodb-limit-Restriction-on-Collection-Names

Let's simplify them to two rules:

• collection names should match regular expression ^[a-zA-Z_][a-zA-Z0-9_]{0,119}$ (that excludes non-latin letters, spaces, dots, dollars, dashes, long names, etc);
• collection names can't start with a reserved prefix _ferretdb_.

We could relax those rules in the future.

• implement collection name validation on collection/table creation;
• add integration test;
• document the difference in rules in README.md;
• add diff dance test.

Tigris is not in scope.