Use submodule way to access oniguruma. And upgrade oniguruma
version from v6.9.3 to v6.9.4_mark1.
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2073

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
---

v2:1.Update the inf file to make VS2019 build pass.
2.Add ignore files in MdeModulePkg.ci.yaml.

The patch is too big, so I put the change on my forked tree.
https://github.com/shenglei10/edk2/tree/oniguruma

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2.18.0.windows.1