build: add clang-tidy configuration file (#15601)

Add a project-style compliant clang-tidy configuration file in the root directory. This configuration will take priority over users own configuration files, so noisy warnings have been removed even though they may be useful, at least for the time being.

.clang-tidy

@@ -0,0 +1,56 @@
+---
+
+Checks: >
+  -*,
+  bugprone-*,
+  cert-env33-c,
+  cert-err34-c,
+  cert-flp30-c,
+  cert-msc30-c,
+  clang-analyzer-*,
+  clang-diagnostics-*,
+  google-*,
+  misc-*,
+  misc-non-copyable-objects,
+  misc-static-assert,
+  performance-*,
+  portability-*,
+  readability-*,
+  -bugprone-assignment-in-if-condition,
+  -bugprone-branch-clone,
+  -bugprone-easily-swappable-parameters,
+  -bugprone-narrowing-conversions,
+  -bugprone-sizeof-expression,
+  -bugprone-unused-return-value,
+  -clang-analyzer-security.insecureAPI.strcpy,
+  -google-readability-function-size,
+  -misc-no-recursion,
+  -misc-unused-parameters,
+  -performance-no-int-to-ptr,
+  -readability-else-after-return,
+  -readability-function-*,
+  -readability-identifier-length,
+  -readability-isolate-declaration,
+  -readability-magic-numbers,
+  -readability-redundant-function-ptr-dereference,
+  -readability-suspicious-call-argument,
+
+CheckOptions:
+  readability-identifier-naming.ClassMemberCase: lower_case
+  readability-identifier-naming.ClassMemberSuffix: _
+  readability-identifier-naming.FunctionCase: lower_case
+  readability-identifier-naming.GlobalConstantCase: CamelCase
+  readability-identifier-naming.GlobalConstantPrefix: k
+  readability-identifier-naming.MemberConstantCase: CamelCase
+  readability-identifier-naming.MemberConstantPrefix: k
+  readability-identifier-naming.NamespaceCase: lower_case
+  readability-identifier-naming.StaticConstantCase: CamelCase
+  readability-identifier-naming.StaticConstantPrefix: k
+  readability-identifier-naming.StructCase: CamelCase
+  readability-identifier-naming.TemplateParameterCase: CamelCase
+  readability-identifier-naming.VariableCase: lower_case
+
+WarningsAsErrors: ''
+
+HeaderFilterRegex: "(src/[cjson|klib|mpack|unicode|xdiff]/).*\\.h$"
+...