feat(duckdb): make it more convenient to access files

[cpcloud]

• feat(duckdb): overwrite views when calling register
• chore: return options.default_backend from _default_backend
• feat(api): return the table from ibis.connect('foo.csv')

[github-actions]

Test Results

       6 files         6 suites   3m 54s ⏱️
3 142 tests 3 128 ✔️ 14 💤 0 ❌
9 420 runs  9 378 ✔️ 42 💤 0 ❌

Results for commit 22c2f74.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Merging #4553 (c4dcca3) into master (6a6a453) will decrease coverage by 0.74%.
The diff coverage is 33.33%.

❗ Current head c4dcca3 differs from pull request most recent head 50036bd. Consider uploading reports for the commit 50036bd to get more accurate results

@@            Coverage Diff             @@
##           master    #4553      +/-   ##
==========================================
- Coverage   92.54%   91.79%   -0.75%     
==========================================
  Files         183      183              
  Lines       20004    20005       +1     
  Branches     2961     2962       +1     
==========================================
- Hits        18513    18364     -149     
- Misses       1114     1253     +139     
- Partials      377      388      +11     

Impacted Files	Coverage Δ
ibis/backends/duckdb/__init__.py	54.28% <ø> (-40.96%)	⬇️
ibis/config.py	91.66% <0.00%> (-8.34%)	⬇️
ibis/backends/base/__init__.py	87.37% <50.00%> (-1.58%)	⬇️
ibis/backends/duckdb/registry.py	32.29% <0.00%> (-60.42%)	⬇️
ibis/backends/duckdb/datatypes.py	64.28% <0.00%> (-35.72%)	⬇️
ibis/backends/duckdb/compiler.py	92.30% <0.00%> (-5.13%)	⬇️
ibis/common/pretty.py	95.31% <0.00%> (-4.69%)	⬇️
ibis/backends/base/sql/alchemy/datatypes.py	88.78% <0.00%> (-2.34%)	⬇️
... and 7 more

[gforsyth]

My connect tests for parquet and CSV are checking list_tables() for registration success -- I like returning the Table better -- probably an isinstance check is enough for those tests now.

[gforsyth]

nice!