feat(ex.location): the new component to show cursor location

[vladimir-popov]

This component shows the current cursor position in configurable format. Comparing to the default
location component, this component can show total number of lines, and may be flexibly configured.

pattern	example
'%2C:%-3L/%T'
'%3L:%-2C'

sections = {
  lualine_a = {
    {
      'ex.location',
      
      -- The pattern to show the cursor position. Here three possible specifiers:
      --  'L' means 'line' - the number of the line where is the cursor now;
      --  'C' means 'column' - the number of the virtual column where is the cursor now;
      --  'T' means 'total' - the total count of lines in the current buffer;
      -- Every specifier can be used in similar maner to %d in the {string.format} function.
      -- The pattern similar to the default 'location' component is '%3L:%-2C'
      pattern = '%2C:%-3L/%T'
    }
  }
}