Implement Cobra CLI tooling, Viper config tooling (#336)

* start pulling out + replacing urfave and config

* replace many many instances of config

* move more stuff => viper

* properly remove urfave

* move some flags to root command

* add testrig commands to root

* alias config file keys

* start adding cli parsing tests

* reorder viper init

* remove config path alias

* fmt

* change config file keys to non-nested

* we're more or less in business now

* tidy up the common func

* go fmt

* get tests passing again

* add note about the cliparsing tests

* reorganize

* update docs with changes

* structure cmd dir better

* rename + move some files around

* fix dangling comma

internal/processing/search.go

@@ -25,7 +25,9 @@ import (
 	"strings"
 
 	"github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -164,7 +166,8 @@ func (p *processor) searchAccountByMention(ctx context.Context, authed *oauth.Au
 
 	// if it's a local account we can skip a whole bunch of stuff
 	maybeAcct := &gtsmodel.Account{}
-	if domain == p.config.Host {
+	host := viper.GetString(config.Keys.Host)
+	if domain == host {
 		maybeAcct, err = p.db.GetLocalAccountByUsername(ctx, username)
 		if err != nil {
 			return nil, fmt.Errorf("searchAccountByMention: error getting local account by username: %s", err)