:sparkles: Implement Page bundling and image handling

This commit is not the smallest in Hugo's history.

Some hightlights include:

* Page bundles (for complete articles, keeping images and content together etc.).
* Bundled images can be processed in as many versions/sizes as you need with the three methods `Resize`, `Fill` and `Fit`.
* Processed images are cached inside `resources/_gen/images` (default) in your project.
* Symbolic links (both files and dirs) are now allowed anywhere inside /content
* A new table based build summary
* The "Total in nn ms" now reports the total including the handling of the files inside /static. So if it now reports more than you're used to, it is just **more real** and probably faster than before (see below).

A site building  benchmark run compared to `v0.31.1` shows that this should be slightly faster and use less memory:

```bash
▶ ./benchSite.sh "TOML,num_langs=.*,num_root_sections=5,num_pages=(500|1000),tags_per_page=5,shortcodes,render"

benchmark                                                                                                         old ns/op     new ns/op     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      101785785     78067944      -23.30%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     185481057     149159919     -19.58%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      103149918     85679409      -16.94%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     203515478     169208775     -16.86%

benchmark                                                                                                         old allocs     new allocs     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      532464         391539         -26.47%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1056549        772702         -26.87%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      555974         406630         -26.86%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1086545        789922         -27.30%

benchmark                                                                                                         old bytes     new bytes     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      53243246      43598155      -18.12%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     105811617     86087116      -18.64%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      54558852      44545097      -18.35%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     106903858     86978413      -18.64%
```

Fixes #3651
Closes #3158
Fixes #1014
Closes #2021
Fixes #1240
Updates #3757

1 files changed, 10 insertions, 0 deletions

diff --git a/deps/deps.go b/deps/deps.go
index a7d77b5b1..ac89d6cd6 100644
--- a/deps/deps.go
+++ b/deps/deps.go
@@ -10,6 +10,7 @@ import (
 	"github.com/gohugoio/hugo/hugofs"
 	"github.com/gohugoio/hugo/metrics"
 	"github.com/gohugoio/hugo/output"
+	"github.com/gohugoio/hugo/source"
 	"github.com/gohugoio/hugo/tpl"
 	jww "github.com/spf13/jwalterweatherman"
 )
@@ -33,6 +34,9 @@ type Deps struct {
 	// The ContentSpec to use
 	*helpers.ContentSpec `json:"-"`
 
+	// The SourceSpec to use
+	SourceSpec *source.SourceSpec `json:"-"`
+
 	// The configuration to use
 	Cfg config.Provider `json:"-"`
 
@@ -122,6 +126,8 @@ func New(cfg DepsCfg) (*Deps, error) {
 		return nil, err
 	}
 
+	sp := source.NewSourceSpec(cfg.Language, fs)
+
 	d := &Deps{
 		Fs:                  fs,
 		Log:                 logger,
@@ -130,6 +136,7 @@ func New(cfg DepsCfg) (*Deps, error) {
 		WithTemplate:        cfg.WithTemplate,
 		PathSpec:            ps,
 		ContentSpec:         contentSpec,
+		SourceSpec:          sp,
 		Cfg:                 cfg.Language,
 		Language:            cfg.Language,
 	}
@@ -194,4 +201,7 @@ type DepsCfg struct {
 
 	// i18n handling.
 	TranslationProvider ResourceProvider
+
+	// Whether we are in running (server) mode
+	Running bool
 }