switch to generating substitution files for DB

[gilesknap]

Now creates substitution files from the database entries in the IOC YAML. like below

I think this is a bit ugly but it works and is readable.
@coretl @GDYendell @niamhdougan take a look if you feel like making it nicer. :-)

################################################################################
# DB substitution file generated by https://github.com/epics-containers/ibek
################################################################################

file "another_test.db" {
pattern 
	{ name,            my_int_enum, clock_rate, db_calculated,         calculated_one } 
	{ "AllObject One", "2",         "dummy",    "HELLO AllObject One", "AllObject One.AllObject One String.1.1.0.True" } 
	{ "AllObject Two", "1",         "1",        "HELLO AllObject Two", "AllObject Two.AllObject Two String.1.1.0.True" } 
}


file "yet_another.db" {
pattern 
	{ name,            my_object, my_float, my_bool } 
	{ "AllObject One", "Ref1",    "1.0",    "True" } 
	{ "AllObject Two", "Ref1",    "1.0",    "True" } 
}


file "test.db" {
pattern 
	{ name,                   ip,          value } 
	{ "Consumer Two With DB", "127.0.0.1", "Ref1.127.0.0.1" } 
}

[gilesknap]

This is a fix for #59