Add introduced contacts as UNVERIFIED

...tests/src/test/java/org/briarproject/BlogManagerTest.java

...est/java/org/briarproject/BlogSharingIntegrationTest.java

...ests/src/test/java/org/briarproject/ForumManagerTest.java

...st/java/org/briarproject/ForumSharingIntegrationTest.java

...st/java/org/briarproject/IntroductionIntegrationTest.java

...ava/org/briarproject/SimplexMessagingIntegrationTest.java

briar-api/src/org/briarproject/api/contact/Contact.java

...-api/src/org/briarproject/api/contact/ContactManager.java

briar-api/src/org/briarproject/api/db/DatabaseComponent.java

...src/org/briarproject/contact/ContactExchangeTaskImpl.java

...core/src/org/briarproject/contact/ContactManagerImpl.java

briar-core/src/org/briarproject/db/Database.java

...r-core/src/org/briarproject/db/DatabaseComponentImpl.java

briar-core/src/org/briarproject/db/JdbcDatabase.java

...re/src/org/briarproject/identity/IdentityManagerImpl.java

.../src/org/briarproject/introduction/IntroduceeManager.java

...tests/src/org/briarproject/blogs/BlogManagerImplTest.java

...ts/src/org/briarproject/db/DatabaseComponentImplTest.java

briar-tests/src/org/briarproject/db/H2DatabaseTest.java

.../org/briarproject/introduction/IntroduceeManagerTest.java