Some suggestions about devcontainer.json, clang-tidy, cmake-format, and ubuntu jimmy.

Hello @lefticus. I admire your work. I have some suggestions and we can discuss about them and then I can create some PRs if they turn out to be good :

In `devcontainer.json`, add these settings for better automatically checking for Clang errors. VSCode shows nicely the problems and underlines the problematics line.
```
"C_Cpp.codeAnalysis.runAutomatically": true, // For automatically run code analysis on save
"C_Cpp.codeAnalysis.clangTidy.enabled": true, // Clang tidy checks are included when it is run code analysis
"C_Cpp.codeAnalysis.exclude": { // Exclude checking in out directory (using presets). Maybe need some other folders too.
"${workspaceFolder}/out/**": true
```

And add extension:
` "cheshirekow.cmake-format" // For automatically run formating cmake files on save`
This extension must have installed `cmake-format`. Because of this, we need to add in `Dockerfile`:
`RUN python3 -m pip install cmake_format`

In .clang-tidy I always like to add CheckOptions for example:
```
CheckOptions:
- { key: readability-identifier-naming.NamespaceCase, value: lower_case }
- { key: readability-identifier-naming.ClassCase, value: CamelCase }
- { key: readability-identifier-naming.StructCase, value: CamelCase }
- { key: readability-identifier-naming.TemplateParameterCase, value: CamelCase }
- { key: readability-identifier-naming.FunctionCase, value: CamelCase }
- { key: readability-identifier-naming.VariableCase, value: lower_case }
- { key: readability-identifier-naming.PrivateMemberSuffix, value: _ }
- { key: readability-identifier-naming.ProtectedMemberSuffix, value: _ }
- { key: readability-identifier-naming.MacroDefinitionCase, value: UPPER_CASE }
- { key: readability-identifier-naming.EnumConstantCase, value: CamelCase }
- { key: readability-identifier-naming.EnumConstantPrefix, value: k }
- { key: readability-identifier-naming.ConstexprVariableCase, value: CamelCase }
- { key: readability-identifier-naming.ConstexprVariablePrefix, value: k }
- { key: readability-identifier-naming.GlobalConstantCase, value: CamelCase }
- { key: readability-identifier-naming.GlobalConstantPrefix, value: k }
- { key: readability-identifier-naming.MemberConstantCase, value: CamelCase }
- { key: readability-identifier-naming.MemberConstantPrefix, value: k }
- { key: readability-identifier-naming.StaticConstantCase, value: CamelCase }
- { key: readability-identifier-naming.StaticConstantPrefix, value: k }
```
This force developers to use the same naming conventions. What do you think?

One more suggestion is to support the new ubuntu Jimmy.