CalciteUtils .CharType should be generic like logicaltypes.FixedBytes

[damccorm]

We have a special "CalciteUtils.CharType" for fixed size char, that should be replaced with a core type like logicaltypes.FixedBytes and support added to AvroUtils and others.

Imported from Jira BEAM-12323. Original Jira may contain additional context.
Reported by: apilloud.

[Abacn]

.remove-labels 'awaiting triage'

[Abacn]

.take-issue