docs(enabledManagers): added list of possible managers, removed references to docker and node (#4594)

This commit adds (back) support for GitLab's 'merge when pipeline succeeds'
feature. This feature needs to be enabled by bot owners explicitely because
of an possible race condition in current GitLab versions.

Closes #3265

Closes #4516

Only changed incorrect use of words and not each and every
grammatical changes.

Refer: #4277

Closes #4106

With Renovate’s github platform code now using git for all file system operations, we need to tell Renovate which gitAuthor to use.

If you had already configured a gitAuthor in your bot config, you do not need to make any change.

Otherwise, to keep functionality as before, you should either:
(1) configure `gitAuthor` to match the bot’s account, or
(2) recreate your bot’s personal access token to include the “user:email” permission so that the bot can retrieve the email itself

BREAKING CHANGE: GitHub bot admins should either configure gitAuthor in their config or generate a new token with “user:email” permissions.

feat: unify file locations

feat(bitbucket): Enable bitbucket reviewers

Document how to sign gitFs commits, remove the disabling of gpg signing.

Closes #3053, Closes #3472