MAJOR: Project rename and preparation for v1.0.0

I hope I haven't missed any for the renames!

lua/outline/providers/markdown.lua

@@ -0,0 +1,25 @@
+local md_parser = require 'outline.markdown'
+
+local M = {}
+
+-- probably change this
+function M.should_use_provider(bufnr)
+  return string.match(vim.api.nvim_buf_get_option(bufnr, 'ft'), 'markdown')
+end
+
+function M.hover_info(_, _, on_info)
+  on_info(nil, {
+    contents = {
+      kind = 'markdown',
+      contents = { 'No extra information availaible!' },
+    },
+  })
+end
+
+---@param on_symbols function
+---@param opts table
+function M.request_symbols(on_symbols, opts)
+  on_symbols(md_parser.handle_markdown(), opts)
+end
+
+return M