Compress symbol table

[nuta]

Currently, a symbol table reserves 2MiB space to store symbols (e.g. function names) of the kernel. Because symbols in Rust tend to be lengthy, they are truncated to 55 characters.

This issue aims to implement a simple symbol table compression to:

• Decrease the kernel image size.
• Print the whole symbol name (avoid truncating).

[nuta]

Ref: LLVM's string table builder: https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/MC/StringTableBuilder.h

[nuta]

Ref: Using trie would be better, as used in Mach-O: https://github.com/llvm/llvm-project/blob/main/lld/MachO/ExportTrie.cpp

[michalfita]

Why do you need to keep the symbol table with the running kernel?