Enable gossip encryption (#14640)

* Enable gossip encryption

* Fix order

* Auto-generate key

* Update gorp fork to include BeginTx

* Add a test for InsertIfExists

And point gorp to a custom branch for now

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

vendor/modules.txt

@@ -108,7 +108,6 @@ github.com/dyatlov/go-opengraph/opengraph
 # github.com/facebookgo/subset v0.0.0-20200203212716-c811ad88dec4
 ## explicit
 # github.com/fatih/color v1.9.0
-## explicit
 github.com/fatih/color
 # github.com/fortytw2/leaktest v1.3.0
 ## explicit
@@ -128,7 +127,7 @@ github.com/glycerine/go-unsnap-stream
 # github.com/go-asn1-ber/asn1-ber v1.4.1
 ## explicit
 github.com/go-asn1-ber/asn1-ber
-# github.com/go-gorp/gorp v2.0.0+incompatible
+# github.com/go-gorp/gorp v2.2.0+incompatible
 ## explicit
 # github.com/go-sql-driver/mysql v1.5.0
 ## explicit
@@ -265,7 +264,7 @@ github.com/mattermost/go-i18n/i18n
 github.com/mattermost/go-i18n/i18n/bundle
 github.com/mattermost/go-i18n/i18n/language
 github.com/mattermost/go-i18n/i18n/translation
-# github.com/mattermost/gorp v2.0.1-0.20190301154413-3b31e9a39d05+incompatible
+# github.com/mattermost/gorp v2.0.1-0.20200527092429-d62b7b9cadfc+incompatible
 ## explicit
 github.com/mattermost/gorp
 # github.com/mattermost/gosaml2 v0.3.2
@@ -292,7 +291,7 @@ github.com/mattn/go-isatty
 # github.com/mattn/go-runewidth v0.0.9
 ## explicit
 github.com/mattn/go-runewidth
-# github.com/mattn/go-sqlite3 v1.11.0
+# github.com/mattn/go-sqlite3 v2.0.3+incompatible
 ## explicit
 github.com/mattn/go-sqlite3
 # github.com/matttproud/golang_protobuf_extensions v1.0.1
@@ -344,6 +343,10 @@ github.com/olekukonko/tablewriter
 ## explicit
 github.com/olivere/elastic/config
 github.com/olivere/elastic/uritemplates
+# github.com/onsi/ginkgo v1.12.0
+## explicit
+# github.com/onsi/gomega v1.9.0
+## explicit
 # github.com/opentracing/opentracing-go v1.1.0
 ## explicit
 github.com/opentracing/opentracing-go
@@ -362,6 +365,8 @@ github.com/philhofer/fwd
 github.com/pkg/errors
 # github.com/pmezard/go-difflib v1.0.0
 github.com/pmezard/go-difflib/difflib
+# github.com/poy/onpar v1.0.0
+## explicit
 # github.com/prometheus/client_golang v1.5.1
 ## explicit
 github.com/prometheus/client_golang/prometheus