Lua: vim.env, vim.{g,v,w,bo,wo} #11442

- Add vim variable meta accessors: vim.env, vim.{g,v,w,bo,wo}
- Redo gen_char_blob to generate multiple blobs instead of just one
  so that multiple Lua modules can be inlined.
- Reorder vim.lua inclusion so that it can use previously defined C
  functions and utility functions like vim.shared and vim.inspect things.
- Inline shared.lua into nvim, but also keep it available in runtime.

runtime/lua/vim/shared.lua

@@ -4,7 +4,7 @@
 -- test-suite. If, in the future, Nvim itself is used to run the test-suite
 -- instead of "vanilla Lua", these functions could move to src/nvim/lua/vim.lua
 
-local vim = {}
+local vim = vim or {}
 
 --- Returns a deep copy of the given object. Non-table objects are copied as
 --- in a typical Lua assignment, whereas table objects are copied recursively.