Update GenericBinaryBuilder to use buffer builders directly.

[HaoYang670]

Which issue does this PR close?

Closes #2104.

Rationale for this change

Don't build binary array from list builder to avoid bugs and extra memory occupation.

What changes are included in this PR?

1. Update the struct of GenericBinaryBuilder
2. Remove the method append_byte and append. (append_value and append_null can achieve all functionalities)
3. More tests to cover the all-null case and builder resetting.
4. Fix some docs

Are there any user-facing changes?

Yes, remove 2 pub methods append_byte and append.

[codecov-commenter]

Codecov Report

Merging #2117 (c3a9be3) into master (3096591) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2117      +/-   ##
==========================================
+ Coverage   83.76%   83.78%   +0.01%     
==========================================
  Files         225      225              
  Lines       59457    59485      +28     
==========================================
+ Hits        49806    49839      +33     
+ Misses       9651     9646       -5     

Impacted Files	Coverage Δ
arrow/src/array/builder/generic_binary_builder.rs	92.00% <100.00%> (+8.66%)	⬆️
parquet_derive/src/parquet_field.rs	65.98% <0.00%> (-0.23%)	⬇️
arrow/src/datatypes/datatype.rs	64.41% <0.00%> (+0.35%)	⬆️
...row/src/array/builder/string_dictionary_builder.rs	91.36% <0.00%> (+0.71%)	⬆️

[tustvold]

An optimisation we use elsewhere is to lazily create the null builder on first null

[HaoYang670]

Currently, This optimization is only used on primitive builder and boolean builder.
We could do a follow-up to use it on all builders.

[ursabot]

Benchmark runs are scheduled for baseline = fd38664 and contender = 1805b30. 1805b30 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ec2-t3-xlarge-us-east-2] ec2-t3-xlarge-us-east-2
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on test-mac-arm] test-mac-arm
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-i9-9960x] ursa-i9-9960x
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-thinkcentre-m75q] ursa-thinkcentre-m75q
Buildkite builds:
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java