feat(FIR-34986): can use COPY to create table

[ptiurin]

Description

Adding ability to use copy command instead of external table. Copy is more efficient and will be supported for longer.
To maintain backwards-compatibility by default dbt-firebolt uses external table and if the users specify strategy: copy in their sources file then copy is used.

Also adding fixes for project installation as tests broke due to dbt-firebolt not being installed in the right directory.
Changes in adapter and catalog files are necessary since external tables weren't picked up before by the DBT's changes resolution mechanism and -full-refresh parameter would write duplicate data.

Checklist

• I have run this code in development and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required/relevant for this PR.
• I have run changie new and committed everything in .changes folder
• I have removed any print or log calls that were added for debugging.
• I have verified that this PR contains only code changes relevant to this PR.
• If further integration tests are now passing I've edited tests/functional/adapter/* to account for this.
• I have pulled/merged from the main branch if there are merge conflicts.
• After pulling/merging main I have run pytest on the included or updated tests/functional/adapter/.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud