recipetool: appendsrcfile(s): use params instead of extraline

recipetool: appendsrcfile(s): use params instead of extraline

appendsrc function relies on oe.recipeutils.bbappend_recipe to
copy files and add the corresponding entries in SRC_URI.

Currently, appendsrc function build itself the new SRC_URI entry to add the
correct subdir param, and gives it using the extralines parameter.
This has 2 drawbacks:
- oe.recipeutils.bbappend_recipe can already do this if we specify the
  correct params, so we have duplicate code
- the duplicated code is not fully functional: for example, it doesn't
  take into account the -m/--machine parameter

So fix this by not using extralines but give correctly formatted params.

Also remove the check for already existing entries as
oe.recipeutils.bbappend_recipe already implement it

The new bbappend file now have the SRC_URI entry after the
FILESEXTRAPATHS so fix the selftest.

Update test_recipetool_appendsrcfile_existing_in_src_uri_diff_params
test because recipetool appendsrcfiles used to not add new src_uri entry
if the entry already exist even with different parameters while
oe.recipeutils.bbappend_recipe adds it if parameters are different (and
remove the old entry)

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>