[p] Improve mail templates

- Add contract UUID
- Fix typos

dfssp/templates/contract.go

@@ -12,6 +12,7 @@ Please download the attached file and open it with the DFSS client.
 const contractDetails = `Signers :
 {{range .Signers}}  - {{.Email}}
 {{end}}
+Contract ID   : {{.ID.Hex}}
 Contract name : {{.File.Name}}
 SHA-512 hash  : {{printf "%x" .File.Hash}}
 Comment       : {{.Comment}}

dfssp/templates/invitation.go

@@ -3,8 +3,8 @@ package templates
 const invitation = `Dear Sir or Madam,
 
 Someone invited you to sign a multiparty contract using the DFSS platform.
-Please download the latest version of DFSS an register a new account using
-this adress mail in order to sign the contract.
+Please download the latest version of DFSS and register a new account using
+this mail address in order to sign the contract.
 
 {{template "contractDetails" .}}
 {{template "signature"}}

dfssp/templates/manager_test.go

@@ -31,6 +31,7 @@ Signers :
   - mail@example.com
   - mail2@example.com
 
+Contract ID   : ` + contract.ID.Hex() + `
 Contract name : name.pdf
 SHA-512 hash  : 010211aa
 Comment       : comment

dfssp/templates/verificationMail.go

@@ -2,7 +2,7 @@ package templates
 
 const verificationMail = `Dear sir or Madam,
 
-You asked to register to the DFSS platform.
+You asked to register on the DFSS platform.
 Please send us your authentication request with
 the following text as token: