SQL - ability to connect directly to resource provider

[jaredmoo]

Use SQL RP URI and subscription id from environment variables in order to skip AAD and connect directly to the resource provider. This is used for SQL internal testing where there is no AAD/ARM frontend so the user has authority to use any subscription id.

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This checklist is used to make sure that common guidelines for a pull request are followed.

General Guidelines

• The PR has modified HISTORY.rst with an appropriate description of the change (see Modifying change log).

Command Guidelines

• Each command and parameter has a meaningful description.
• Each new command has a test.

(see Authoring Command Modules)

[yugangw-msft]

Please fix the style check error by adding a new empty line

[codecov-io]

Codecov Report

Merging #2832 into master will increase coverage by 0.23%.
The diff coverage is 71.42%.

@@            Coverage Diff             @@
##           master    #2832      +/-   ##
==========================================
+ Coverage   62.88%   63.11%   +0.23%     
==========================================
  Files         464      464              
  Lines       25890    25921      +31     
  Branches     3944     3949       +5     
==========================================
+ Hits        16281    16361      +80     
+ Misses       8590     8508      -82     
- Partials     1019     1052      +33

Impacted Files	Coverage Δ
...ure-cli-sql/azure/cli/command_modules/sql/_util.py	84.21% <71.42%> (-8.65%)	⬇️
...-cli-find/azure/cli/command_modules/find/custom.py	88% <0%> (-5.75%)	⬇️
...li-role/azure/cli/command_modules/role/commands.py	84.44% <0%> (-2.52%)	⬇️
...ure-cli-core/azure/cli/core/commands/parameters.py	70.96% <0%> (-2.16%)	⬇️
...torage/azure/cli/command_modules/storage/custom.py	85.83% <0%> (-1.18%)	⬇️
src/azure-cli-core/azure/cli/core/parser.py	81.37% <0%> (ø)	⬆️
...cli-role/azure/cli/command_modules/role/_params.py	100% <0%> (ø)	⬆️
src/azure-cli-core/azure/cli/core/application.py	89.32% <0%> (+0.48%)	⬆️
src/azure-cli-core/azure/cli/core/_profile.py	85.25% <0%> (+1.07%)	⬆️
...etwork/azure/cli/command_modules/network/custom.py	63.46% <0%> (+1.08%)	⬆️
... and 1 more

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