Redis Functions - Move Lua related variable into luaCtx struct

The following variable was renamed:
1. lua_caller 			-> script_caller
2. lua_time_limit 		-> script_time_limit
3. lua_timedout 		-> script_timedout
4. lua_oom 			-> script_oom
5. lua_disable_deny_script 	-> script_disable_deny_script
6. in_eval			-> in_script

The following variables was moved to lctx under eval.c
1.  lua
2.  lua_client
3.  lua_cur_script
4.  lua_scripts
5.  lua_scripts_mem
6.  lua_replicate_commands
7.  lua_write_dirty
8.  lua_random_dirty
9.  lua_multi_emitted
10. lua_repl
11. lua_kill
12. lua_time_start
13. lua_time_snapshot

This commit is in a low risk of introducing any issues and it
is just moving varibales around and not changing any logic.
