General engine improvements (#437)

* Add exchange manager to engine

* Several improvements for engine and friends

1) New file.Exists func
2) gRPC TLS cert expiration date check and regeneration
3) New donation var for use across the codebase
4) Use Go log package until the logger is initialised

* Add cert tests and create dir tree if it doesn't exist for file.Write

* Link up donation address to documentation tool plus minor adjustments

* Fix remaining donation addrs

* Move non-needed reload exchange funcs

* Revert accidental config_example.json changes 🕯️

* Use go logger for logging until the logger has initiliased, otherwise no output will be seen

* Link up portfolio delay val and other fixes

* Run go mod tidy after dependabot PR

* Address nitterinos

cmd/documentation/documentation.go

@@ -100,11 +100,12 @@ type DocumentationDetails struct {
 // Attributes defines specific documentation attributes when a template is
 // executed
 type Attributes struct {
-	Name         string
-	Contributors []Contributor
-	NameURL      string
-	Year         int
-	CapitalName  string
+	Name            string
+	Contributors    []Contributor
+	NameURL         string
+	Year            int
+	CapitalName     string
+	DonationAddress string
 }
 
 func main() {
@@ -199,6 +200,21 @@ func main() {
 				URL:           "https://github.com/zeldrinn",
 				Contributions: 1,
 			},
+			{
+				Login:         "starit",
+				URL:           "https://github.com/starit",
+				Contributions: 1,
+			},
+			{
+				Login:         "Jimexist",
+				URL:           "https://github.com/Jimexist",
+				Contributions: 1,
+			},
+			{
+				Login:         "lookfirst",
+				URL:           "https://github.com/lookfirst",
+				Contributions: 1,
+			},
 		}...)
 
 		if verbose {
@@ -378,11 +394,12 @@ func GetContributorList(repo string) ([]Contributor, error) {
 // GetDocumentationAttributes returns specific attributes for a file template
 func GetDocumentationAttributes(packageName string, contributors []Contributor) Attributes {
 	return Attributes{
-		Name:         GetPackageName(packageName, false),
-		Contributors: contributors,
-		NameURL:      GetGoDocURL(packageName),
-		Year:         time.Now().Year(),
-		CapitalName:  GetPackageName(packageName, true),
+		Name:            GetPackageName(packageName, false),
+		Contributors:    contributors,
+		NameURL:         GetGoDocURL(packageName),
+		Year:            time.Now().Year(),
+		CapitalName:     GetPackageName(packageName, true),
+		DonationAddress: core.BitcoinDonationAddress,
 	}
 }