Refactoring: renaming "selfCert" to "createIdentity"

app/controllers/webmin.controller.js

app/lib/computation/blockGenerator.js

app/lib/entity/identity.js

app/lib/streams/multicaster.js

app/service/IdentityService.js

test/integration/branches2.js

test/integration/branches_pending_data.js

test/integration/branches_revert.js

test/integration/branches_revert2.js

test/integration/branches_switch.js

test/integration/certification_chainability.js

test/integration/collapse.js

test/integration/crosschain-test.js

test/integration/forwarding.js

test/integration/http_api.js

test/integration/identity-absorption.js

test/integration/identity-clean-test.js

test/integration/identity-expiry.js

test/integration/identity-kicking.js

test/integration/identity-test.js