chore: Add a basic clang-tidy config

[royjacobson]

Tried to filter for low noise high value, but this is still much too noisy for something like a CI stage. Statistics of running on the whole DF + helio code base:

    265 [bugprone-narrowing-conversions]
    115 [clang-diagnostic-unqualified-std-cast-call]
     87 [readability-inconsistent-declaration-parameter-name]
     51 [performance-move-const-arg]
     45 [modernize-make-unique]
     30 [performance-unnecessary-value-param]
     25 [readability-make-member-function-const]
     24 [readability-container-size-empty]
     18 [google-explicit-constructor]
     16 [modernize-deprecated-headers]
     14 [modernize-return-braced-init-list]
     13 [readability-named-parameter]
     13 [google-default-arguments]
     10 [readability-static-definition-in-anonymous-namespace]
      8 [bugprone-unchecked-optional-access]
      7 [clang-diagnostic-unused-const-variable]
      6 [readability-redundant-member-init]
      5 [modernize-use-emplace]
      5 [misc-unused-alias-decls]
      5 [clang-diagnostic-unused-result]
      5 [bugprone-too-small-loop-variable]
      4 [performance-no-int-to-ptr]
      4 [modernize-use-equals-delete]
      4 [modernize-unary-static-assert]
      4 [clang-diagnostic-unused-but-set-variable]
      4 [bugprone-integer-division]
      3 [readability-non-const-parameter]
      3 [modernize-pass-by-value]
      3 [misc-misplaced-const]
      3 [clang-diagnostic-unused-variable]
      3 [bugprone-macro-parentheses]
      3 [bugprone-exception-escape]
      2 [readability-use-anyofallof]
      2 [readability-redundant-string-init]
      2 [performance-for-range-copy]
      2 [modernize-use-using]
      2 [misc-unused-using-decls]
      2 [misc-uniqueptr-reset-release]
      2 [clang-diagnostic-parentheses]
      2 [bugprone-unhandled-exception-at-new]
      2 [bugprone-suspicious-missing-comma]
      2 [bugprone-incorrect-roundings]
      1 [readability-redundant-string-cstr]
      1 [readability-redundant-smartptr-get]
      1 [readability-redundant-declaration]
      1 [readability-redundant-control-flow]
      1 [readability-const-return-type]
      1 [performance-unnecessary-copy-initialization]
      1 [performance-faster-string-find]
      1 [modernize-raw-string-literal]
      1 [misc-redundant-expression]
      1 [google-build-explicit-make-pair]
      1 [clang-diagnostic-unused-function]
      1 [clang-diagnostic-implicit-const-int-float-conversion]
      1 [clang-diagnostic-final-dtor-non-final-class]
      1 [bugprone-use-after-move]
      1 [bugprone-unused-raii]
      1 [bugprone-signed-char-misuse]
      1 [bugprone-assignment-in-if-condition]

Second commit fixes a few of the found issues.

[dranikpg]

Narrowing is a whole problem on its own. We use different types throughout the project for arg positions/sizes/etc and they're often casted back and forth

Maybe we can at first focus only df core parts (no helio, no tests)?

51 [performance-move-const-arg]

Wow 👀 We should look at those

[chakaz]

Yes please!! Great work!
Perhaps we can aim to enable the disabled ones in future fix-it weeks. Is there some tag for such tasks?

[chakaz]

Wow, nice catch!

[royjacobson]

Narrowing is a whole problem on its own. We use different types throughout the project for arg positions/sizes/etc and they're often casted back and forth

Yeah, I disabled the narrowing warning at the end :) I don't thing that going over 260 warnings and fixing things like int64_t s = v.size() manually is not cost effective.