Update the MySQL collation to default

[mvl22]

We should update
collation-server = utf8mb4_unicode_ci
to
collation-server = utf8mb4_0900_ai_ci

https://github.com/cyclestreets/cyclestreets-setup/blob/master/utility/installBaseWebserver.sh#L211

[si-the-pie]

Explanation of the parts of the collation name at:

https://stackoverflow.com/a/9531221/225876

It also lists some ideas for generating all the SQL commands required to change a database.

[mvl22]

Fixed in 3f684d5, which will mean MySQL now uses the default.