OfficePreDisabledWarnings applies to all of RNW, not just Office

[asklar]

PropertySheets\Warnings.props:

  <PropertyGroup>
    <!-- Office pre-disabled warnings -->
    <!--
        C4201 - nonstandard extension used : nameless struct/union
        C4505 - 'function' : unreferenced local function has been removed
        C4456 - declaration of 'identifier' hides previous local declaration
        C4458 - declaration of 'identifier' hides class member
        C4702 - unreachable code
      -->
    <OfficePreDisabledWarnings>4201;4505;4456;4458;4702</OfficePreDisabledWarnings>

<!-- more stuff ... -->

  <ItemDefinitionGroup>
    <ClCompile>
      <!-- /permissive- by default to enforce standards conformance, unless ENABLEPermissive has been set -->
      <AdditionalOptions Condition="'$(ENABLEPermissive)' == ''">/permissive- %(AdditionalOptions)</AdditionalOptions>
      <DisableSpecificWarnings>$(OfficePreDisabledWarnings);$(ExtraWarningsToDisable);$(DisableSpecificWarnings)</DisableSpecificWarnings>

[chrisglein]

Do we remove these warning disables? (fix the code)
Or are these disables more general? (as they are being applied for everyone and have for many versions)

Preference to go remove these and fix up the code.

Next step here would be to start removing these warning disables one by one and cataloging the code that breaks. Either fix those or dump them in this issue so we can collectively start burning them down.