feat(action): provide new attributes for link and title

[Tom4U]

Please read and mark the following check list before creating a pull request:

• I read and followed the CONTRIBUTING.md guide.
• I read and followed the New Feature Checklist guide.

Short description of what this resolves:

Provides the ability to use a link and title (if icon is set) for action component:

Using [routerLink] with link attribute:
<nb-action link="/" icon="nb-home" title="Home"></nb-action>

Using href for links other than [routerLink]:
<nb-action href="http://somesite.com" icon="nb-paper-plane" title="Some Site"></nb-action>

Closes #814

[yggg]

Hi @Tom4U! Thanks a lot for the contribution! Could you please, address the comments.
And probably, to simplify *ngIf conditions it's better to move icon check to ng-container. Something like this:

<ng-container *ngIf="icon; else projectedContent">
  <a *ngIf="link" ...>...</a>
  <a *ngIf="href" ...>...</a>
  <a *ngIf="!link && !href" ...>...</a>
</ng-container>

<ng-template #projectedContent>
  <ng-content></ng-content>
</ng-template>
...

What do you think?

[codecov]

Codecov Report

Merging #1046 into master will decrease coverage by 0.67%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1046      +/-   ##
==========================================
- Coverage   79.52%   78.85%   -0.68%     
==========================================
  Files         202      200       -2     
  Lines        6243     6073     -170     
  Branches      495      469      -26     
==========================================
- Hits         4965     4789     -176     
- Misses       1162     1169       +7     
+ Partials      116      115       -1

Impacted Files	Coverage Δ
...work/theme/components/actions/actions.component.ts	78.78% <100%> (+2.12%)	⬆️
...work/theme/components/tooltip/tooltip.directive.ts	95.08% <0%> (-4.92%)	⬇️
...work/theme/components/popover/popover.directive.ts	86.88% <0%> (-4.3%)	⬇️
...mework/theme/components/layout/layout.component.ts	76.16% <0%> (ø)	⬆️
...work/theme/components/popover/popover.component.ts	100% <0%> (ø)	⬆️
...work/theme/components/tooltip/tooltip.component.ts	100% <0%> (ø)	⬆️
...rc/framework/theme/components/cdk/overlay/index.ts	100% <0%> (ø)	⬆️
.../theme/components/cdk/overlay/overlay-container.ts	100% <0%> (ø)	⬆️
...nts/cdk/overlay/dynamic/dynamic-overlay-handler.ts
.../components/cdk/overlay/dynamic/dynamic-overlay.ts
... and 1 more

outdated

[nnixaa]

@Tom4U thanks for your contribution!