Unify dask-sql API with blazing SQL

[nils-braun]

Fixes #58

I have implemented (parts of) the blazingSQL API of the context - especially .sql, .create_table, .explain and .drop_table.

What is still missing:

• let create_table also work on a hive cursor
• think about implementing all the file system functions (e.g. .s3). However - in dask they are not really needed as all the parameters can just be passed via the call to create_table. -> I decided against implementing them for now. Everything can be achieved with the methods already present. Maybe in a later step we can add them also here.

[codecov-io]

Codecov Report

Merging #63 into main will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main       #63   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           31        32    +1     
  Lines         1249      1296   +47     
  Branches       161       167    +6     
=========================================
+ Hits          1249      1296   +47     

Impacted Files	Coverage Δ
dask_sql/java.py	100.00% <ø> (ø)
dask_sql/context.py	100.00% <100.00%> (ø)
dask_sql/input_utils.py	100.00% <100.00%> (ø)
dask_sql/physical/rel/custom/create.py	100.00% <100.00%> (ø)

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[nils-braun]

The PR contains a first experimental implementation of an hive input.
It is not really well tested so far (and I have also not written unittests for it) - so I guess this part should be improved in the next release.