Translations for TrustIndicatorView trust levels

The TrustIndicatorView can display 5 different trust levels:

• ANONYMOUS
• UNVERIFIED
• VERIFIED
• OURSELVES
• default

In order to implement features like #1052 (closed) and make the trust levels easier to understand we need descriptive translations of trust levels and what they mean for a contact.

I suggest to create the translation keys:

• contact_trust_level_anonymous
• contact_trust_level_unverified
• contact_trust_level_verified
• contact_trust_level_ourselves
• contact_trust_level_default

The this can be used to show the symbolic trust level and the descriptive text side by side, e.g: