Enabling static analysis on indexer plugin and fixing errors (#5220)

* Enabling code analysis, and treating warnings as errors

* Error CA1724 The type name Settings conflicts in whole or in part with the namespace name 'Microsoft.PowerToys.Settings'. Change either name to eliminate the conflict. Microsoft.Plugin.Indexer C:\repos\powertoys\src\modules\launcher\Plugins\Microsoft.Plugin.Indexer\Settings.cs 9 Active

* Removing keyword "Interface" from namespace to fix fxcop warnings

* Fixing static analysis warnings on ContextMenuLoader

* Fixing general exception warnings for static analysis

* Fixing public list variables, non static methods, and general exception warning

* Implementing IDisposable on OleDBSearch although in practice these objects were already being disposed.

Also Validated we were not using user input directly for sql strings.

* Removing VS generated comments from dispose methods as per PR feedback.

* Setting translated text to use current culture as per PR feedback.

* Explicity specifying 'internal' access modifier for Indexer 'Main' class, as per PR feedback

* Updating to FxCop 3.0.0

src/modules/launcher/Plugins/Microsoft.Plugin.Indexer/Microsoft.Plugin.Indexer.csproj

@@ -23,6 +23,7 @@
     <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
     <WarningLevel>4</WarningLevel>
     <Optimize>false</Optimize>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
@@ -38,6 +39,10 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.0.0">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
     <PackageReference Include="System.Data.OleDb" Version="4.7.1" />
     <PackageReference Include="tlbimp-Microsoft.Search.Interop" Version="1.0.0">
       <NoWarn>NU1701</NoWarn>