refactor: feature_csv_activation.py: move tx helper functions to methods
refactor: feature_csv_activation.py: move tx helper functions to methods

This allows to get rid of the global miniwallet variable and to specify
the used node self.nodes[0] at only one place, instead of passing it to
every tx creation/send method again and again.

Can be reviewed with --ignore-all-space --color-moved=dimmed-zebra

prusnak/bitcoin,Xekyo/bitcoin,domob1812/bitcoin,fanquake/bitcoin,anditto/bitcoin,qtumproject/qtum,ElementsProject/elements,jlopp/statoshi,rnicoll/bitcoin,jambolo/bitcoin,lateminer/bitcoin,jambolo/bitcoin,GroestlCoin/bitcoin,namecoin/namecore,mruddy/bitcoin,JeremyRubin/bitcoin,ajtowns/bitcoin,ElementsProject/elements,bitcoinsSG/bitcoin,jlopp/statoshi,lateminer/bitcoin,yenliangl/bitcoin,domob1812/bitcoin,Xekyo/bitcoin,anditto/bitcoin,bitcoinknots/bitcoin,ajtowns/bitcoin,Xekyo/bitcoin,GroestlCoin/GroestlCoin,qtumproject/qtum,tecnovert/particl-core,ElementsProject/elements,domob1812/namecore,jlopp/statoshi,fanquake/bitcoin,tecnovert/particl-core,sipsorcery/bitcoin,jambolo/bitcoin,andreaskern/bitcoin,GroestlCoin/bitcoin,instagibbs/bitcoin,JeremyRubin/bitcoin,fujicoin/fujicoin,GroestlCoin/bitcoin,Xekyo/bitcoin,namecoin/namecore,AkioNak/bitcoin,GroestlCoin/bitcoin,ajtowns/bitcoin,kallewoof/bitcoin,pataquets/namecoin-core,GroestlCoin/GroestlCoin,fujicoin/fujicoin,namecoin/namecore,yenliangl/bitcoin,jlopp/statoshi,rnicoll/bitcoin,pataquets/namecoin-core,yenliangl/bitcoin,tecnovert/particl-core,kallewoof/bitcoin,apoelstra/bitcoin,anditto/bitcoin,bitcoinknots/bitcoin,dscotese/bitcoin,jamesob/bitcoin,bitcoin/bitcoin,domob1812/bitcoin,fujicoin/fujicoin,qtumproject/qtum,fanquake/bitcoin,prusnak/bitcoin,GroestlCoin/GroestlCoin,bitcoinknots/bitcoin,jamesob/bitcoin,mruddy/bitcoin,apoelstra/bitcoin,Xekyo/bitcoin,andreaskern/bitcoin,dscotese/bitcoin,mm-s/bitcoin,bitcoin/bitcoin,particl/particl-core,particl/particl-core,sstone/bitcoin,jambolo/bitcoin,GroestlCoin/GroestlCoin,domob1812/namecore,rnicoll/bitcoin,anditto/bitcoin,bitcoinknots/bitcoin,AkioNak/bitcoin,namecoin/namecore,sstone/bitcoin,MarcoFalke/bitcoin,qtumproject/qtum,domob1812/namecore,sipsorcery/bitcoin,mruddy/bitcoin,rnicoll/bitcoin,anditto/bitcoin,bitcoinsSG/bitcoin,apoelstra/bitcoin,bitcoinsSG/bitcoin,namecoin/namecoin-core,namecoin/namecoin-core,andreaskern/bitcoin,fujicoin/fujicoin,mm-s/bitcoin,lateminer/bitcoin,achow101/bitcoin,AkioNak/bitcoin,dscotese/bitcoin,pataquets/namecoin-core,apoelstra/bitcoin,apoelstra/bitcoin,mm-s/bitcoin,GroestlCoin/GroestlCoin,JeremyRubin/bitcoin,kallewoof/bitcoin,dscotese/bitcoin,kallewoof/bitcoin,particl/particl-core,instagibbs/bitcoin,bitcoin/bitcoin,fujicoin/fujicoin,domob1812/namecore,achow101/bitcoin,rnicoll/bitcoin,ajtowns/bitcoin,mm-s/bitcoin,qtumproject/qtum,pataquets/namecoin-core,mruddy/bitcoin,lateminer/bitcoin,domob1812/bitcoin,yenliangl/bitcoin,fanquake/bitcoin,jamesob/bitcoin,ajtowns/bitcoin,instagibbs/bitcoin,MarcoFalke/bitcoin,namecoin/namecore,fujicoin/fujicoin,sipsorcery/bitcoin,mm-s/bitcoin,namecoin/namecore,pataquets/namecoin-core,domob1812/namecore,bitcoinsSG/bitcoin,bitcoin/bitcoin,particl/particl-core,kallewoof/bitcoin,MarcoFalke/bitcoin,bitcoin/bitcoin,prusnak/bitcoin,sstone/bitcoin,jlopp/statoshi,fanquake/bitcoin,prusnak/bitcoin,ElementsProject/elements,andreaskern/bitcoin,achow101/bitcoin,sipsorcery/bitcoin,JeremyRubin/bitcoin,mm-s/bitcoin,MarcoFalke/bitcoin,MarcoFalke/bitcoin,domob1812/bitcoin,namecoin/namecoin-core,achow101/bitcoin,sipsorcery/bitcoin,bitcoinknots/bitcoin,particl/particl-core,domob1812/bitcoin,qtumproject/qtum,kallewoof/bitcoin,AkioNak/bitcoin,tecnovert/particl-core,yenliangl/bitcoin,anditto/bitcoin,instagibbs/bitcoin,GroestlCoin/bitcoin,instagibbs/bitcoin,sstone/bitcoin,bitcoinsSG/bitcoin,achow101/bitcoin,fanquake/bitcoin,jlopp/statoshi,JeremyRubin/bitcoin,apoelstra/bitcoin,jambolo/bitcoin,dscotese/bitcoin,yenliangl/bitcoin,Xekyo/bitcoin,MarcoFalke/bitcoin,prusnak/bitcoin,andreaskern/bitcoin,AkioNak/bitcoin,bitcoin/bitcoin,namecoin/namecoin-core,rnicoll/bitcoin,bitcoinsSG/bitcoin,domob1812/namecore,sstone/bitcoin,ajtowns/bitcoin,tecnovert/particl-core,achow101/bitcoin,jambolo/bitcoin,particl/particl-core,GroestlCoin/bitcoin,JeremyRubin/bitcoin,mruddy/bitcoin,sstone/bitcoin,ElementsProject/elements,sipsorcery/bitcoin,lateminer/bitcoin,lateminer/bitcoin,AkioNak/bitcoin,jamesob/bitcoin,andreaskern/bitcoin,tecnovert/particl-core,pataquets/namecoin-core,GroestlCoin/GroestlCoin,namecoin/namecoin-core,instagibbs/bitcoin,ElementsProject/elements,jamesob/bitcoin,prusnak/bitcoin,jamesob/bitcoin,namecoin/namecoin-core,mruddy/bitcoin,qtumproject/qtum,dscotese/bitcoin