[llvm-readobj][AArch64][ELF][PAC] Support ELF AUTH constants (#72713)

This patch adds llvm-readobj support for:

- Dynamic R_AARCH64_AUTH_* relocations (including RELR compressed AUTH
relocations) as described here:
https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#auth-variant-dynamic-relocations

- .note.AARCH64-PAUTH-ABI-tag section as defined here
https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#elf-marking