feat(ui5-table): introduce Single and Multi selection modes

[niyap]

Feature: SingleSelect and MultiSelect modes introduced:

• property mode (SingleSelect | MultiSelect)
• event selection-change

Usage

<ui5-table mode="SingleSelect"></ui5-table>
<ui5-table mode="MultiSelect"></ui5-table>

table.addEventListener("selection-change",  event => {});

FIXES: #2659

[ilhan007]

Overall it looks good, besides the comments inline, please check:

• When rows pop in and the mode is MultiSelect, there is this mixture of white/grey backgrounds, that is not present prior to the change.

• just to remind to test it in IE

[ilhan007]

Would be better if you do this in declarative way, e.g. to create a state (getter or private property) and use in the template:
<ui5-checkbox ?checked={{allRowsSelected}} class="ui5-table-select-all-checkbox">
Can you try if would work this way?

[ilhan007]

change -> ui5-change (non-conflict event names are recommended)

[ilhan007]

We will revisit all the API of all the components but this can be improved on the spot, let's use the bullets representation of enum options

        * Defines the mode of the <code>ui5-table</code>.
        * <br><br>
   	 * Available options are:
   	 * <ul>
   	 * <li><code>MultiSelect</code></li>
   	 * <li><code>SingleSelect</code></li>
   	 * <li><code>None</code></li>
   	 * <ul>

[ilhan007]

enter -> <code>Enter</code>

[ilhan007]

This object will be re-created each time we enter the function

you can do this

this[`_handle${this.mode}`]](event);

or extract the "mappings" as static getter:

static get SELECTION_HANDLERS_MAPPING() {
   return {
            "SingleSelect": "_handleSingleSelect",
			"MultiSelect": "_handleMultiSelect",
    }
}

[ilhan007]

this.rows.filter(item => item.selected) is something you need in several places, add a getter for that:

get selectedRows() {
    return this.rows.filter(item => item.selected)
}

[ilhan007]

Do you use "isInViewport" - it maybe left from merge conflicts resolution, please double check

[ilhan007]

There is also related code with that, you can remove it :

     // 155:TableRow.js
	cell.firstInRow = (index === 0);

[ilhan007]

add since especially here, but it won't hurt to add since for the private ones.

For since use 1.0.0-rc.14 (rc.13 has been released)

 * Defines the visual indication and behavior of the <code>ui5-table-row</code>.
 * <br><br>
		 * Available options are:
		 * <ul>
		 * <li><code>Active</code></li>
		 * <li><code>Inactive</code></li>
		 * <ul>
		 ```

[ilhan007]

13 -> 14

[ilhan007]

since

[ilhan007]

use the type TableRowType.Active instead of hard-coded strings

[ilhan007]

Add JS doc when the row-click is fired after this change

[ilhan007]

just
await fetchI18nBundle("@ui5/webcomponents"),

use Promise.all for multiple async tasks

[ilhan007]

FYI: use 1.0.0-rc.15 as since, because we had to release RC.14 due to 2 urgent issues that we fixed and had to release