BB: Add hook-scripts support for Repos + Server

[tuxmaster5000]

The needed endpoints:

Repos:
List hook-scripts :
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-repository/#api-api-latest-projects-projectkey-repos-repositoryslug-hook-scripts-get
Remove hook-scripts:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-repository/#api-api-latest-projects-projectkey-repos-repositoryslug-hook-scripts-scriptid-delete
Create/update hook-scripts:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-repository/#api-api-latest-projects-projectkey-repos-repositoryslug-hook-scripts-scriptid-put

Server itself:
Remove hook-script:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-system-maintenance/#api-api-latest-hook-scripts-scriptid-delete

Download script:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-system-maintenance/#api-api-latest-hook-scripts-scriptid-content-get

Get infos about the script:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-system-maintenance/#api-api-latest-hook-scripts-scriptid-get

Upload an script:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-system-maintenance/#api-api-latest-hook-scripts-post

Update an script:
https://developer.atlassian.com/server/bitbucket/rest/v906/api-group-system-maintenance/#api-api-latest-hook-scripts-scriptid-put

[gonchik]

Thanks for suggestion @tuxmaster5000 ,
once I will have a capacity will do.
Or I will be happy for your PR :)