Adding ScanAllSets to the api

[kmpm]

I made a new function in the API for getting all result sets from sql.Rows.
My use case for this is a 3rd party application that uses mssql and have stored procedures returning multiple different results.
Possibly also a solution for #114

Tests can be run if you have a Sql Server up an running somewhere and run the tests with the tag with_mssql.

$ go test -tags with_mssql ./...

# if you need a custom connection string for the server you can use the MSSQL_URL environment variable
$ MSSQL_URL="sqlserver://user:pwd@dbhost" go test -tags with_mssql ./...

[codecov]

Codecov Report

Attention: 19 lines in your changes are missing coverage. Please review.

Comparison is base (80c2cc6) 82.74% compared to head (40f2666) 80.41%.

Files	Patch %	Lines
dbscan/dbscan.go	33.33%	13 Missing and 1 partial ⚠️
pgxscan/pgxscan.go	0.00%	3 Missing ⚠️
sqlscan/sqlscan.go	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #115      +/-   ##
==========================================
- Coverage   82.74%   80.41%   -2.34%     
==========================================
  Files           5        5              
  Lines         510      531      +21     
==========================================
+ Hits          422      427       +5     
- Misses         73       89      +16     
  Partials       15       15              

Flag	Coverage Δ
unittests	80.41% <32.14%> (-2.34%)	⬇️

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[georgysavva]

Hi @kmpm, thank you for adding this new feature to the library. The code and tests look great.

Let me think about it from the design point of view for a bit, though. If I have any questions, I will let you know.

[kmpm]

@georgysavva, you closed the issue I was refering to as completed so I kind of hoped you would have accepted the PR, but no.
How can I be of assistance to get this PR merged, or can I help to fix something similar, compatible with multiple result sets, with another design.

[georgysavva]

@kmpm, thank you for your work, and sorry for taking so much time to merge your PR. Here is the new release containing this feature: https://github.com/georgysavva/scany/releases/tag/v2.1.0