Add findroot function for selecting telescope file search base dir

lua/findroot.lua

@@ -0,0 +1,50 @@
+local Path = require("plenary.path")
+local source_basedir_markers = {
+	".telescope-root",
+	".editorconfig",
+	"build.sbt",
+	"package.json",
+	"setup.py",
+	".git",
+}
+function find_upwards_any(base, filenames)
+	local folder = Path:new(base)
+	local root = Path.path.root(folder)
+
+	while folder:absolute() ~= root do
+		for _, filename in ipairs(filenames) do
+			local p = folder:joinpath(filename)
+			if p:exists() then
+				return p
+			end
+		end
+		folder = folder:parent()
+	end
+	return ""
+end
+
+local function find_dir(base)
+	print("base: ", base)
+	if base == nil then
+		base = vim.loop.cwd()
+	end
+	--@type Path
+	local search_root
+	search_root = find_upwards_any(base, source_basedir_markers)
+	print("search_root: ", search_root)
+	if search_root ~= "" then
+		local file = search_root:_split()
+		if file[#file] == ".telescope-root" then
+			local target = search_root:parent():joinpath(search_root:head(1))
+			if target:exists() then
+				return tostring(target)
+			end
+		else
+			return tostring(search_root:parent())
+		end
+	else
+		return base
+	end
+end
+
+return find_dir