Add first .clang-tidy file #2135

Job	Run time
scanbuild	6m 36s
test-tcti-config	14m 12s
build-test (ubuntu-20.04, gcc)	4m 32s
test-mbedtls (ubuntu-20.04)	3m 2s
build-test (ubuntu-20.04, clang)	4m 30s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	2m 56s
build-test (fedora-32, gcc)	4m 42s
build-test (fedora-32, clang)	4m 56s
build-test (opensuse-leap, gcc)	4m 41s
build-test (opensuse-leap, clang)	4m 50s
build-test (ubuntu-22.04, gcc)	4m 39s
build-test (ubuntu-22.04, clang)	4m 41s
test-coverage	5m 15s
test-fuzz	2m 41s
test-no-crypto-build	1m 22s
coverity-test	0s
build-test (alpine-3.15, gcc)	4m 4s
build-test (alpine-3.15, clang)	4m 46s
	1h 22m 25s

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