Change WiX convert error messages to information messages where appropriate

[MarkStega]

No description provided.

[MarkStega]

1. For some reason, after getting an update to VS2022 17.1 preview there was an issue finding the .Net 6.0.101 SDK during the build; I added a global.json file to the root that excludes pre-release sdk's

2. The readme,md is updated to have the start of 'Developing WiX' information

3. WixConverter.cs now has a method 'OnInformation'. It displays an infomation level message prefixed with [Converted] to indicate that the construct in question was updated. I changed the 'Errors' member to 'Messages' but did not go through the test fixtures to change the name of the locals. I will if desired. The methodology of deciding whether to replace OnError with OnInformation was that if a transform was performed then OnInformation was appropriate.

[rseanhall]

1. We generate a global.json in src which already excludes prerelease versions: https://github.com/wixtoolset/wix4/blob/212a7179408758b27fea5a12274f739a5205b2d7/src/internal/SetBuildNumber/SetBuildNumber.proj#L41
   We haven't typically been interested in spending the time to support preview versions of VS or .NET Core, but there have been breaking changes in the past that we would have noticed earlier if someone had been brave enough to use the preview version. We would be interested in the details of this problem before solving it this way, and would prefer to do that in a separate PR.

2. We would prefer to take this in a separate PR so that the doc changes and conversion changes can be reviewed and merged independent of each other.

[MarkStega]

Sean,

Not a problem -- I dropped the global.json from this PR and will do a build demonstrating what I saw that lead me to the addition of same. I am building using the release version of VS2022.

I also moved the documentation changes to PR #99

[robmen]

Sorry, I missed (or didn't get) the notice that this PR was out of draft. I've rebased it to current and did a bit of clean-up in PR #135.

Thanks for doing the work to bring this about.

[rseanhall]

I don't think I've ever gotten a notification that a PR was marked ready for review. I would have expected that review request to have generated a notification, though.