Updated where leader key is set and made var in lv-settings (#474)

- Setting leader-key in the init.lua file. You want to set the leader as
  soon as possible so that it's the same everywhere. With the leader
  being set in the lua/lv-which-key/init.lua it resulted in mappings that
  used `<leader>` in the lua/keymappings.lua mapping the the defualt
  leader-key of `\`
- Added the O.leader_key to the lv-settings.lua file so the leader-key
  can be set there, which seems to make more sense.
- Added handling for when the leader-key is `<Space>`. This could be
  made more robust to include other special keys, but I don't think
  many/any of the other special keys would be used as a leader-key (ie
  <BS>, <CR>, <Tab>, <Esc>, <Up|Down|Right|Left>, etc.)

Co-authored-by: Christian Chiarulli <chris.machine@pm.me>

init.lua

@@ -1,5 +1,15 @@
 require('lv-globals')
 vim.cmd('luafile '..CONFIG_PATH..'/lv-settings.lua')
+
+-- Set leader
+if O.leader_key == ' ' or O.leader_key == 'space' then
+    vim.api.nvim_set_keymap('n', '<Space>', '<NOP>', {noremap = true, silent = true})
+    vim.g.mapleader = ' '
+else
+    vim.api.nvim_set_keymap('n', O.leader_key, '<NOP>', {noremap = true, silent = true})
+    vim.g.mapleader = O.leader_key
+end
+
 require('settings')
 require('lv-gitblame')
 require('lv-matchup')
@@ -34,8 +44,6 @@ if O.extras then
     require('lv-vimtex')
 end
 
-
-
 -- TODO is there a way to do this without vimscript
 vim.cmd('source '..CONFIG_PATH..'/vimscript/functions.vim')