Add SkipOnPrefix and SkipOnSuffix plugins

Problem/Motivation

We have a process pipeline that looks like this:

  uri:
    -
      plugin: substr
      source: uri
      start: 0
      length: 34
    -
      plugin: skip_on_value
      method: row
      value: 'public://ckfinder/.ckfinder/cache/'

It would be better if we could combine those in to one.

Steps to reproduce

Proposed resolution

Add a plugin for skip_on_prefix and skip_on_suffix that uses str_starts_with and str_ends_with

Remaining tasks

User interface changes

API changes

Data model changes