Blazor overview updates 8.0

[guardrex]

Fixes #30285
Addresses #28161

Notes

• When 🔪 here, I made sure that the Hosting Models and Components overview received a couple of items that they didn't have to ensure that we don't lose any coverage. The entire Components section of the Blazor overview can be 🔪 because we have all of that coverage back in the Components overview article. Assuming that you like the cut, I dropped the content for all versions, but do you want to keep the components coverage for <8.0 coverage?
• I merged the prior Blazor Web Apps and Blazor WebAssembly content with an emphasis on the former.
• For >=8.0, we don't have a BWA image, and I didn't keep the Blazor WASM image for >=8.0 coverage. Do you want any images in >=8.0 coverage?

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Internal previews

📄 File	🔗 Preview link
aspnetcore/blazor/components/index.md	ASP.NET Core Razor components
aspnetcore/blazor/hosting-models.md	ASP.NET Core Blazor hosting models
aspnetcore/blazor/index.md	ASP.NET Core Blazor
aspnetcore/release-notes/aspnetcore-3.0.md	aspnetcore/release-notes/aspnetcore-3.0
aspnetcore/tutorials/choose-web-ui.md	Choose an ASP.NET Core web UI

[danroth27]

I have a few suggestions for your consideration.

Also, can we include in this PR a cleanup pass on the two bulleted lists at the beginning of the doc? The two lists seem pretty repetitive. I think the first list should summarize what Blazor is, and the second list should enumerate its advantages. I also want to stop using the phrase "instead of JavaScript" to avoid alienating frontend JavaScript devs that might be interested in Blazor. Instead of saying "instead of JavaScript" we should focus on how Blazor makes building web apps easier and more productive.

[guardrex]

@danroth27 ... Updates made ... ready for another 👀.

[danroth27]

Looks good to me. Thanks!