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

The regex versioner supports arbitrary, user-defined versioning
methods; it provides building blocks in the way of interacting capture
groups within a user-defined regex which can be combined to support
arbitrary use-cases.

Uses a new `versionConfig` option to configure this scheme -- this
feature is enabled dynamically for any new versioner which includes the
optional `configure?(new_config: string)` interface. Warns if used with
an invalid scheme.

`rebaseConflictedPrs` is used to enable or disable auto-rebase
in case of merge conflicts with the master branch. It is `true`
by default which means branches will be rebased if there are conflicts
in a PR. By setting it to `false`, Renovate no longer will rebase it
with the master branch if there are merge conflicts.

Refer #4184

Closes #3929

Closes #4106

Signed-off-by: Matous Dzivjak <matous.dzivjak@kiwi.com>

Adds a table to the commit message body listing all the updates in a commit. Disabled by default for now, so opt in by setting commitBodyTable=true

Drops References column and embeds links in Package column.

Closes #3855

This reverts commit e3937fa8.

This reverts commit c9bfccfd.

Closes #3640

Rewrites hostRules for increased flexibility. Includes renames of existing fields within a hostRule:
- `endpoint` -> `baseUrl`
- `host` -> `hostName`

Additionally, `domainName` has been added. Migration scripts should take care of these for users but it's recommended to update configs to match the new fields anyway.