[PORT]Surface LG CacheScope out in LG file options

[Danieladu]

Fixes #3109

Original C# PR: microsoft/botbuilder-dotnet#4982

Description

Support the following options in LG file to specify the cache scope

> !# @cacheScope= global/local/none   // by default is local

Changes

Support setting LG cache scope in LG file

> !# @cacheScope= global // global cache
> !# @cacheScope= local // local cache
> !# @cacheScope= none // none cache
> !# @cacheScope= xxx // fallback to local cache

Global cache is effective in the life cycle of an evaluation

For example:

var templates = Templates.ParseFile("xxx.lg");
var result1 = templates.Evaluate("template", null, new EvaluationOptions { CacheScope = LGCacheScope.Global});

// The second evaluation would drop all the results cached before.
var result2 = templates.Evaluate("template", null, new EvaluationOptions { CacheScope = LGCacheScope.Global});

Option name case insensitive

> !# @cacheScope= global // ok
> !# @CACHESCOPE= global // ok
> !# @cachescope= global // ok
...

Cache scope would follow the scope of the entrance LG

For example:
a.lg:

> !# @cacheScope= global
 [import](b.lg)

b.lg

> !# @cacheScope= none
# template1
- ${template2()} ${template2()}

# template2
- ${rand(1, 10000000)}

Code:

var templates = Templates.parseFile("a.lg");
var result = templates.evaluate("template1"); // the second "template2" would use the cache of the first evaluate result

[coveralls]

Pull Request Test Coverage Report for Build 411426822

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 18 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.04%) to 84.46%

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Files with Coverage Reduction	New Missed Lines	%
libraries/adaptive-expressions/src/triggerTrees/node.ts	2	90.51%
libraries/botbuilder-lg/src/evaluationOptions.ts	2	89.02%
libraries/botbuilder-lg/src/evaluator.ts	14	91.78%

Totals
Change from base Build 411425122:	-0.04%
Covered Lines:	17607
Relevant Lines:	19925

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💛 - Coveralls

[joshgummersall]

Not sure why the ADO tests are failing, the Github ones are green though!