Add theme support

[Blake-goofy]

This PR adds theme support for all xaml windows.
Many windows were completely unusable in any of the dark themes that ssms offers such as Dark and Moonlight Glow and Mystical Forest.

All screenshots here show the Dark theme which has a purple accent color, but that color will change depending on the theme. For example the primary button will be green when using Mystical Forest theme.

I also took the opportunity to sync up the style between windows while keeping the same feel of the extension.

Before

After

[Blake-goofy]

I just removed AllUsers="true" to make install easier for testing.

[alex-bochkov]

Could you please try to reduce the code duplication where possible? I think a ResourceDictionary might help here.
The same applies to the C# code. I want to make sure it is easy to reuse and not too difficult to hook into a new form.

**ChatGPT**
1) ResourceDictionary (most common for shared UI pieces, styles, templates)
Define reusable pieces in a separate .xaml file: SharedResources.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style x:Key="MyButtonStyle" TargetType="Button">
        <Setter Property="Background" Value="LightBlue"/>
    </Style>

</ResourceDictionary>

Reference it in another XAML:

<Window.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="SharedResources.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Window.Resources>

[Blake-goofy]

Yes, I will keep that in mind moving forward. Thanks for the feedback.

[Blake-goofy]

@alex-bochkov, I took the liberty of attempting to harmonize the tools window headings to match the GitHub sync window. I like the link to the wiki (see image in the top comment).

[Blake-goofy]

I made 2 non-theme related changes. Both changes were on the schema compare window.

1) Lazy-load definitions

Schema compare previously built full source and target definition scripts for every difference row during compare completion.

That behavior caused large memory/CPU spikes on big schemas and could freeze or crash SSMS before results rendered.

The implementation now loads definition text only for the selected difference row (and on Copy actions), which keeps initial rendering responsive.

2) Synchronized definition scrolling

The Source Definition and Target Definition panes now synchronize vertical and horizontal scrolling.

When one definition pane is scrolled, the other pane follows to the same offset so side-by-side review stays aligned.

[Blake-goofy]

A couple more sample screenshots:

Before

After

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Before

After