just for convenience's sake

if the node fails to start (and we're expecting it to) return to us the
node object anyway

we also signal to collect all of its stderr logs by setting stderr
on the tailableproc that backs the node

Changelog-Fixed: Plugins: if an option has a type int or bool, return the option as that type to the plugin's init

we loosely enforce that the specified type must be one of the listed
options. you can still cause an error because we're not checking the
default value you're passing in ...

not sure if this is totally necessary, should we jsut let clightning
enforce the input?

also: convert the stored int value from 'int' to 's64'

atoi fails silently, returning a zero. instead we use the more robust
strtoll which will allow us fail with an error.

we also make the parsing for bools stricter, only allowing plausibly
boolean values to parse.

we also check that the node isn't running now, for extra pedancity