13271 support dashed extension names

Task 13271 - Make `create_extension` quote extension names properly.

Based on issue report and PR: https://github.com/TMXCredit/pg_power/pull/40

## Changes
* Update `create_extension` and `drop_extension` methods to quote extension names
* Add a "test" to migration to verify uuid-ossp extension can be created and dropped properly.

## RSpec
```
Finished in 0.80869 seconds
88 examples, 0 failures, 3 pending
```

## Doc

Not affected:
```
Files:          42
Modules:        39 (    0 undocumented)
Classes:         7 (    0 undocumented)
Constants:       8 (    0 undocumented)
Methods:       132 (    3 undocumented)
 98.39% documented

Undocumented Objects:

(in file: lib/pg_power/connection_adapters/postgresql_adapter/foreigner_methods.rb)
PgPower::ConnectionAdapters::PostgreSQLAdapter::ForeignerMethods#dependency_sql

(in file: lib/pg_power/create_index_concurrently.rb)
PgPower::CreateIndexConcurrently::Migrator.included
PgPower::CreateIndexConcurrently::MigrationProxy.included
```