ipa: libipa: Introduce Algorithm class template

The algorithms are using the same function names with specialized
parameters. Instead of duplicating code, introduce a libipa Algorithm
class which implements a base class with template parameters in libipa,
and use it in each IPA.

As we now won't need an algorithm class for each IPA, move the
documentation to libipa, and make it agnostic of the IPA used. While at
it, fix the IPU3::Algorithm::Awb documentation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

src/ipa/ipu3/algorithms/awb.cpp

@@ -193,6 +193,9 @@ Awb::Awb()
 
 Awb::~Awb() = default;
 
+/**
+ * \copydoc libcamera::ipa::Algorithm::configure
+ */
 int Awb::configure(IPAContext &context,
 		   [[maybe_unused]] const IPAConfigInfo &configInfo)
 {
@@ -373,6 +376,9 @@ void Awb::calculateWBGains(const ipu3_uapi_stats_3a *stats)
 	}
 }
 
+/**
+ * \copydoc libcamera::ipa::Algorithm::process
+ */
 void Awb::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
 {
 	calculateWBGains(stats);
@@ -394,6 +400,9 @@ constexpr uint16_t Awb::threshold(float value)
 	return value * 8191;
 }
 
+/**
+ * \copydoc libcamera::ipa::Algorithm::prepare
+ */
 void Awb::prepare(IPAContext &context, ipu3_uapi_params *params)
 {
 	/*