Add first .clang-tidy file #2146

Job	Run time
coverity-test	0s
build-test (ubuntu-20.04, gcc)	1m 13s
scanbuild	1m 7s
build-test (ubuntu-20.04, clang)	1m 8s
test-coverage	1m 20s
build-test (fedora-32, gcc)	1m 15s
test-fuzz	1m 15s
build-test (fedora-32, clang)	1m 12s
test-mbedtls (ubuntu-20.04)	2m 48s
test-no-crypto-build	1m 32s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	2m 49s
build-test (opensuse-leap, gcc)	1m 21s
build-test (opensuse-leap, clang)	1m 23s
test-tcti-config	1m 25s
build-test (ubuntu-22.04, gcc)	1m 27s
build-test (ubuntu-22.04, clang)	1m 25s
build-test (alpine-3.15, gcc)	1m 26s
build-test (alpine-3.15, clang)	1m 26s
	25m 32s

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