Adds Map & Enum support, round-trip & benchmark tests (#8353)

# Which issue does this PR close?

- Part of #4886
- Related to #8274 and
#8298

# Rationale for this change

This PR adds Map and Enum encoders to the arrow-avro crate writer, along
with new benchmark tests for remaining types and round-trip tests.

# What changes are included in this PR?

New encoders:
**Map**
**Enum**

Corresponding changes in support of these encoders in FieldEncoder and
FieldPlan

## Additional round trip tests in `mod.rs`

New tests follow existing file read pattern

- simple_fixed
- duration_uuid
- nonnullable.impala.avro
- decimals
- enum

## Additional benchmark tests for data types

- Utf8
- List<Utf8>
- Struct
- FixedSizeBinary16
- UUID
- IntervalMonthDayNanoDuration
- Decimal32(bytes)
- Decimal64(bytes)
- Decimal128(bytes)
- Decimal128(fixed16)
- Decimal256(bytes)
- Map
- Enum

# Are these changes tested?

Yes, additional complex type unit tests have been added for Map and
Enum. The rest of the PR beyond the new types are tests themselves. All
tests, new and existing, pass.

# Are there any user-facing changes?

n/a, arrow-avro crate is not yet public

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Co-authored-by: Connor Sanders <[email protected]>
Co-authored-by: Andrew Lamb <[email protected]>

Author: 3 people