Add exact commit and tag information in recorded metacello directives

[guillep]

This PR adds commit and tag information in recorded metacello directives.
It is the best I can do at recording the downloaded versions from metacello without touching iceberg 🙂
I think I managed to do this without breaking any filetree/tonel support (without iceberg)

The rationale behind this is to be able to track exactly what was loaded for the following scenarios:

• dependencies on floating branches
• CI builds

The new record output looks like follows.
It's a bit verbose but it's useful.
Two things to notice from the example:

• that here I'm loading master from XMLParserHTML, yet metacello tells me exactly what it loaded
  also.
• other dependencies are based on tags. The output provides all tags in addition of the commit SHAs.

This could be improved in the future with a short/lessverbose print. This would require touching iceberg a bit to access short commitishes from metacello integration.

linear load : baseline [BaselineOfOrderPreservingDictionary]
    load : Collections-BitmapCharacterSet -- git@github.com:pharo-contributions/BitmapCharacterSet.git[1.2.7, 1.2.x](9400f95e97d61e575989162c8514dd8268b06980)
    load : Collections-OrderPreservingDictionary -- git@github.com:pharo-contributions/OrderPreservingDictionary.git[1.5.0, 1.5.x](480ff3d62be2722d4a5da8f2a074085dc9e38988)
    load : XML-Parser -- git@github.com:pharo-contributions/XML-XMLParser.git[3.5.0, 3.5.x](0effb9130748e417844886b3cb5992644757b206)
    load : Collections-BitmapCharacterSet-Tests -- git@github.com:pharo-contributions/BitmapCharacterSet.git[1.2.7, 1.2.x](9400f95e97d61e575989162c8514dd8268b06980)
(480ff3d62be2722d4a5da8f2a074085dc9e38988)
    load : XML-Parser-Tests -- git@github.com:pharo-contributions/XML-XMLParser.git[3.5.0, 3.5.x](0effb9130748e417844886b3cb5992644757b206)
    load : XML-Parser-Tests-Conformance -- git@github.com:pharo-contributions/XML-XMLParser.git[3.5.0, 3.5.x](0effb9130748e417844886b3cb5992644757b206)
    load : Collections-OrderPreservingDictionary-GTExtensions -- git@github.com:pharo-contributions/OrderPreservingDictionary.git[1.5.0, 1.5.x](480ff3d62be2722d4a5da8f2a074085dc9e38988)
    load : XML-Parser-GTExtensions -- git@github.com:pharo-contributions/XML-XMLParser.git[3.5.0, 3.5.x](0effb9130748e417844886b3cb5992644757b206)
    load : XML-ParserHTML-Core -- git@github.com:pharo-contributions/XML-XMLParserHTML.git[master](df3caea136ef358484287c7ee273fa10c3901aaa)
    load : XML-ParserHTML-Tests -- git@github.com:pharo-contributions/XML-XMLParserHTML.git[master](df3caea136ef358484287c7ee273fa10c3901aaa)

[guillep]

CI is green, tests unrelated

And we already see this in action in the build's log!

MetacelloNotification: Loaded -> Spec2-Code-Diff-Morphic --- github://pharo-spec/Spec:Pharo12/src(8d688aa)
MetacelloNotification: Loaded -> Spec2-Code-Backend-Tests --- github://pharo-spec/Spec:Pharo12/src(8d688aa)
MetacelloNotification: Loaded -> Sindarin --- github://pharo-spec/ScriptableDebugger:Pharo12/src(19e80e9)
MetacelloNotification: Loaded -> Sindarin-Tests --- github://pharo-spec/ScriptableDebugger:Pharo12/src(19e80e9)
MetacelloNotification: Loaded -> Athens-SVG-PathConverter --- unresolved
MetacelloNotification: Loaded -> Geometry --- github://pharo-contributions/Geometry:master/src(5e18270)
MetacelloNotification: Loaded -> Geometry-Tests --- github://pharo-contributions/Geometry:master/src(5e18270)
MetacelloNotification: Loaded -> NumericInterpolator --- github://pharo-graphics/NumericScales:v1.03/src(b3540fe)
MetacelloNotification: Loaded -> NumericNoise --- github://pharo-graphics/NumericScales:v1.03/src(b3540fe)
MetacelloNotification: Loaded -> NumericInterpolator-Tests --- github://pharo-graphics/NumericScales:v1.03/src(b3540fe)