RFR: 8312425: [vectorapi] AArch64: Optimize vector math operations with SLEEF

[Hamlin Li]

Hi,
Can you help to review the patch?
This pr is based on previous work and discussion in [pr 16234](https://github.com/openjdk/jdk/pull/16234), [pr 18294](https://github.com/openjdk/jdk/pull/18294).

Compared with previous prs, the major change in this pr is to integrate the source of sleef (for the steps, please check `src/jdk.incubator.vector/linux/native/libvectormath/README`), rather than depends on external sleef things (header or lib) at build or run time.
Besides of this change, also modify the previous changes accordingly, e.g. remove some uncessary files or changes especially in make dir of jdk.

Besides of the code changes, one important task is to handle the legal process.

Thanks!

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Commit messages:
 - minor
 - add maintenance nodes
 - merge master
 - remove unnecessary changes
 - resolve build erorrs
 - add [generated] src from sleef
 - fix jni includes
 - rename
 - resolve magicus's comments
 - fix variable name in github workflow
 - ... and 13 more: https://git.openjdk.org/jdk/compare/6ae1cf12...3ab4795d

Changes: https://git.openjdk.org/jdk/pull/18605/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18605&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312425
  Stats: 14582 lines in 20 files changed: 14535 ins; 1 del; 46 mod
  Patch: https://git.openjdk.org/jdk/pull/18605.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18605/head:pull/18605

PR: https://git.openjdk.org/jdk/pull/18605