Import database

[hououou]

This PR is to add support for importing databases. We joint queries based on the schema.cypher, copy.cypher and macro.cypher(files created by export database), getting the query like "create node table xxx; create rel table xxx;copy from xxxx;". Then we execute the generated multiple query statements. Currently, due to we do not support DDL and copy statements in one transaction, each single query statement in generated multiple query statement has its own auto transaction. This should be refactored after we support DDL and Copy statements in one transaction.

[andyfengHKU]

Let's also open an issue about removing ImportDB operator and instead reuse StandaloneCall operator and we make importDB as a pragma function

[codecov]

Codecov Report

Attention: Patch coverage is 94.62366% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 93.52%. Comparing base (29f2534) to head (181f31f).
Report is 18 commits behind head on master.

Files	Patch %	Lines
src/main/client_context.cpp	78.94%	4 Missing ⚠️
src/planner/operator/logical_operator.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2964      +/-   ##
==========================================
+ Coverage   93.50%   93.52%   +0.02%     
==========================================
  Files        1121     1125       +4     
  Lines       42950    43081     +131     
==========================================
+ Hits        40161    40293     +132     
+ Misses       2789     2788       -1     

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