Suggestion: Allow customizing all symbols on the ASCII map

[MilesBHuff]

Please explain your feature request to the best of your abilities:

Not all symbols are customizable on the ASCII map. At present, we can only customize the townblocktypes; and this leaves a lot of symbols unchangeable.

The biggest downside of this lack of customizability, is it prevents me from implementing a monospaced version of the ASCII map in my server's config. There's a a suggestion to monospace the ASCII map by default here: #6114.

Can be done at the same time as #6115.

[MilesBHuff]

Thank you!!