[New Migration Experience] Add updating Default data collection path in extension settings

[krritik]

User can now update the default path for Data collection at Extension Settings.

Extension Settings changes -

1. If user does not set path in Extension Settings -
   DataCollection starts at "%userprofile%\AppData\Roaming\azuredatastudio\PerfData"
2. If user set path in Extension Settings and path does not exist -
   DataCollection starts at "%userprofile%\AppData\Roaming\azuredatastudio\PerfData"
3. If user set path in Extension Settings and path exists -
   DataCollection starts at user given path.

[coveralls]

Pull Request Test Coverage Report for Build 6836463930

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.002%) to 41.568%

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Files with Coverage Reduction	New Missed Lines	%
extensions/notebook/src/dialog/configurePython/configurePathPage.ts	1	57.02%

Totals
Change from base Build 6828665189:	-0.002%
Covered Lines:	30784
Relevant Lines:	69355

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💛 - Coveralls

[krritik]

@cpichuka, Do we want to take this in current release?