Add ssl option to uri for postgres

[jusguy]

Pull Request check-list

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Description of change

Added support for the ssl option to the Postgres URI. For example:

postgres://localhost/sequelize_test?ssl=true

The way I chose to support this was assigning any query parameters from the URI into dialectOptions. Then each dialects ConnectionManager.connect() can use the parameters the same as if they were used in the constructor with options.dialectOptions.

Closes #10015

Related #9712, #6932, #5891

[sushantdhiman]

Please add some tests in https://github.com/sequelize/sequelize/blob/master/test/unit/configuration.test.js#L57

Assert that dialectOptions got new entries as specified in connection string

[codecov]

Codecov Report

Merging #10025 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #10025      +/-   ##
==========================================
+ Coverage   96.38%   96.38%   +<.01%     
==========================================
  Files          63       63              
  Lines        9382     9386       +4     
==========================================
+ Hits         9043     9047       +4     
  Misses        339      339

Impacted Files	Coverage Δ
lib/sequelize.js	96.62% <100%> (+0.04%)	⬆️

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[jusguy]

Sorry about the commit mistakes, I am newer to GitHub and still figuring out the nuances of pull requests.

[sushantdhiman]

Thanks @justinkalland

[gaganpreet]

Is this going to be released on npm? Just came across this issue and tried changing sslmode=require to ssl=true in my connection string. No dice. Using latest Sequelize version (4.42.0).