Store n steps for a test definition.

Each steps has:

• an id
• actions to performed (ckeditor) 
• expected results (ckeditor)
• a rank

We can (through web UI or REST API):

• add a step,
• remove a step,
• edit a step
• reorder steps

Field checklist:

• Tracker Field Structure
  • Specific properties => NO
  • Field can be switch to another type (only sb/msb) => NO
  • Shared Fields => NO
  • Import/Export XML =>YES
  • Field is duplicated on tracker inheritance (both tracker and project creation) => YES
  • Definition is NOT given through SOAP @deprecated => YES
  • Definition is given through REST (representations) => YES
  • Migrate field from TV3 (if not done) => NO
  • Does new field can be used for burndown? => NO
  • Can the field be required? => NO
  • What level of permissions this field supports? => Standard
• Artifacts
  • Export/import CSV => NO
  • What does ‘None’ mean for this field? => N/A
  • Default value => Empty
  • Field is involved in notifications => Not included
  • New value is sent in notifications => NO
  • Diff of the field appears in changesets => Only show that "Something changed", actual diff might come later on
  • Get/create/update NOT through SOAP @deprecated => YES
  • New value is Copied on Artifact copy => NO
  • New value can be used in semantic => NO
  • New value can be updated on masschanges => NO
  • On an artifact with artifact links, on creating directly a child the field can be used => NO
• Reports
  • Field is searchable through criteria => NO
  • Field is displayed as a column in table => NO
  • Field is used to sort => NO
  • Field is used for aggregates => NO
  • Field is used to build charts => NO
  • Field is used to build cardwall => NO
• Angular
  • Create/ edit modal => YES
  • Cardwall edit in place => NO
  • Card field in planning v2 => NO
  • Card field in kanban + filter + highlight => NO
  • Does field can be directly updated in Cardwall => NO
  • Modal edit Release => NO
  • Modal add a Task => NO
• User documentation is accurate => YES
• Update test suite (auto or manual) => YES

 +----------+   n+-----------+   1+----------+
 | Campaign |----| Test Exec |----| Test Def |
 +----------+    |-----------|    |----------|
                 | status    |    | title    |
                 | comment   |    | desc     |
                 | timer     |    +----------+
                 | …         |         |
                 +-----------+         |
                      |                |
                      |                |
                      |n               |n
                 +-----------+   1+----------+
                 | Step Exec |----| Step Def |
                 |-----------|    |----------|
                 | status    |    | action   |
                 | comment   |    | expected |
                 | exec_by   |    +----------+
                 | …         |
                 +-----------+

CREATE TABLE IF NOT EXISTS plugin_testmanagement_step(
    id INT(11) UNSIGNED NOT NULL auto_increment PRIMARY KEY,
    action TEXT,
    expected TEXT
);
CREATE TABLE IF NOT EXISTS plugin_testmanagement_changeset_value_stepdef(
    changeset_value_id INT(11) NOT NULL,
    step_id INT(11) UNSIGNED,
    PRIMARY KEY(changeset_value_id, step_id),
    INDEX reverse_idx(step_id, changeset_value_id)
);