upgrade relx dep to latest mustache branch commit

Remove erlydtl and replace with mustache

enable parse transformations in rebar config

don't load package registry unless there are pkg deps to solve

include _checkouts in release lib dirs if it exists

read in application details into app_info after fetch

Avoid topsorting deps twice

They can be culled and reused in one sort pass.

support templates even when not run as escript

handle transitive deps being promoted

merge_locks crashed if a config didn't have a deps entry

remove warning if header not found, could be in a macro

Support 18.0+

fix template listing (re-add escript_incl_extra)

Fixes regression from 3a63bec39f (diff-31d7a50c99c265ca2793c20961b60979L4)
which meant listing templates doesn't work (rebar3 new help)

real bootstrapping

Track code path

Symlink existing default deps when in new profile

Should fix #360

fix erl_first_files to check entire path of file

run project wide pre-compile hooks after deps have compiled

set the dep as the project app before running hooks

don't duplicate hooks for top level app