FS-7508 FS-7517: [build] Convert the build over to automake, though there is still room to fix

the autoconf portion to detect the correct location of libopenh264

Basic conversion for vpx too.
Borrowing from ldns handling, setup mod_vpx to prompt for the required library when the module is enabled

src/mod/codecs/mod_vpx/Makefile.am

@@ -0,0 +1,14 @@
+include $(top_srcdir)/build/modmake.rulesam
+MODNAME=mod_vpx
+
+if HAVE_VPX
+mod_LTLIBRARIES = mod_vpx.la
+mod_vpx_la_SOURCES  = mod_vpx.c
+mod_vpx_la_LIBADD   = $(switch_builddir)/libfreeswitch.la
+mod_vpx_la_LDFLAGS  = -lvpx -avoid-version -module -no-undefined -shared
+else
+install: error
+all: error
+error:
+	$(error You must install your distros libvpx-dev to build mod_vpx)
+endif