[feat] Add Support for Monolithic kernel

[Azure-stars]

The monolithic plugin can be seen at starrt-next, and CI results are here.

It add axns to manage resources under different kernel architecture. And the arceos backbone can be used to support monolithic kernel by enabling uspace feature.

[hky1999]

Overall, the coding LGTM.

Two questions remained:

1. Is it appropriate to merge (1) ucontext, (2) syscall processing and (3) axmm support for process address space related to the monolithic kernel before the axhal reconstruction is completed @equation314 ?
2. Can we make axmm independent, and combine it with axaddrspace?

[aarkegz]

Overall, the coding LGTM.

Two questions remained:

1. Is it appropriate to merge (1) ucontext, (2) syscall processing and (3) axmm support for process address space related to the monolithic kernel before the axhal reconstruction is completed @equation314 ?

2. Can we make axmm independent, and combine it with axaddrspace?

1. is lgtm. For 2. I agree with you, axmm and axaddrspace is closely related.