multi: add max local csv config option

To allow nodes more control over the amount of time that their funds
will be locked up, we add a MaxLocalCSVDelay option which sets the
maximum csv delay we will accept for all channels. We default to the
existing constant of 10000, and set a sane minimum on this value so that
clients cannot set unreasonably low maximum csv delays which will result
in their node rejecting all channels.

sample-lnd.conf

@@ -384,6 +384,12 @@ bitcoin.node=btcd
 ; will scale the value according to the channel size.
 ; bitcoin.defaultremotedelay=144
 
+; The maximum number of blocks we will limit the wait that our own funds are
+; encumbered by in the case when our node unilaterally closes. If a remote peer
+; proposes a channel with a delay above this amount, lnd will reject the
+; channel.
+; bitcoin.maxlocaldelay=2016
+
 ; The smallest HTLC we are willing to accept on our channels, in millisatoshi.
 ; bitcoin.minhtlc=1
 
@@ -550,6 +556,12 @@ litecoin.node=ltcd
 ; will scale the value according to the channel size.
 ; litecoin.defaultremotedelay=144
 
+; The maximum number of blocks we will limit the wait that our own funds are
+; encumbered by in the case when our node unilaterally closes. If a remote peer
+; proposes a channel with a delay above this amount, lnd will reject the
+; channel.
+; litecoin.maxlocaldelay=2016
+
 ; The smallest HTLC we are willing to accept on our channels, in millisatoshi.
 ; litecoin.minhtlc=1