Changes

feat(jobs,pipelines): add next-gen presubmit jobs and pipelines for TiDB (#3572)

Close #3482

This pull request introduces a series of changes to streamline and
enhance Jenkins pipeline jobs for the `pingcap/tidb` repository. It
includes the creation of new pipeline configurations, updates to pod
specifications, and improvements to job definitions. The most
significant changes involve renaming and restructuring job files, adding
declarative pipeline definitions, and specifying resource limits for
Kubernetes pods.

### Pipeline Job Updates:
* Renamed and restructured the `pull_next_gen_real_tikv_test.groovy`
file to `pull_build_next_gen.groovy` with updated job definitions and
script paths. This change simplifies job naming and aligns it with the
repository structure.
* Added new pipeline job configurations for various tasks, including
`pull_check_next_gen`, `pull_mysql_test_next_gen`,
`pull_real_tikv_test_next_gen`, `pull_unit_test_ddlv1_next_gen`, and
`pull_unit_test_next_gen`. These jobs follow a standardized format and
include parameters, properties, and SCM definitions for better
maintainability.
[[1]](diffhunk://#diff-e338d6a7c305264472d2a3de7296459546b1df17fc282cdcb86cbcfb317f92a8R1-R42)
[[2]](diffhunk://#diff-0334569d6450dd7db4d6d21aaa22bdad0e36238517bbac31a30f54531202a6b0R1-R42)
[[3]](diffhunk://#diff-604dd064083b7bc4e24c26b22fdb2ef0cf5f921e6d3b7ebdf82417c106cdcbdbR1-R42)
[[4]](diffhunk://#diff-4c70d4edb1166ea76fac7d02791e9503379823b1f6865178f548449595a3f61dR1-R42)
[[5]](diffhunk://#diff-797029c7328baab4d6977b80c495615c9e1d6020960771071650095fbda13965R1-R42)

### Pipeline Definitions:
* Created declarative pipeline definitions for `pull_build_next_gen` and
`pull_check_next_gen`. These pipelines define stages such as debugging,
checkout, build, testing, and post-build actions, ensuring a structured
and efficient CI/CD process.
[[1]](diffhunk://#diff-5d07f8a0316f7735c0722f8e9c4a63832c0fdef8f6ce42ee56dac322b85304c1R1-R116)
[[2]](diffhunk://#diff-66715fe1dc4720d172cf083c0878f51b0e72c9a7b381ecad93b03a45f109dbd2R1-R91)

### Kubernetes Pod Specifications:
* Added Kubernetes pod specifications (`pod.yaml`) for
`pull_build_next_gen` and `pull_check_next_gen`. These specify container
images, resource limits, volume mounts, and lifecycle hooks to optimize
the execution environment for Jenkins jobs.
[[1]](diffhunk://#diff-8fe759cd3b97404ed3cc8deda8987a4bd49eca5d065fae3b153f1a54a0281b56R1-R95)
[[2]](diffhunk://#diff-b2cfd2b025e27fc39b741fc2f8110c5b3cba2b61910d2202a6f55fa6d4a810b7R1-R98)
 (commit: 4c6499d)